Yes as far as the focal length is concerned (though the OM lenses don't use the 35mm equivalent focal length (ie 80-300) they use use the what I assume is the physical focal length (40-150).
But referring to the lens as a "F8" lens is confusing because the amount of light the aperture admits is equal to an F4 lens as far as I know.

I haven't referred to this lens "as an F8", I've said that the hypothetical 80-300mm lens it will behave comparably to would be an F8.

Hopefully this should make it clear.

@Thomas Kachadurian, if you go on the Olympus website, they show 35mm equivalent for all their lenses, so even Olympus is using 35mm as the standard. If you are mad at it, you should also take it up with Olympus themselves.

@Steven Wandy, if you go to the Olympus website and click on a lens, one of the main highlights is the 35mm eq. For example, the 8-25mm says "16-50 35MM Equivalent Focal Length" clear in the middle of the lens page. If you wanted to make the same lens in FF, you don't have to crop the FOV, so you make a lens with double the focal lengths (16-50), and you have a larger sensor behind it, so you no longer need F4 to achieve similar results, instead you'll get there with F8.

@OSPhoto: Does Olympus call it an F8? They are comparing it to the angle of view. The equivalent aperture illusion is only on DPR

You asked when 35mm became the GMT, I'm simply reminding you that Olympus / OM System themselves are using it as the GMT, so you can argue with them also if you don't like it. Standards are used so that people have a reference point. Maybe you can, but I can't memorize what every focal length on every sensor size practically looks like. There has to be a reference.

They are only citing focal length equivalent, so the f-stop equivalent is irrelevant. Giving people the 35mm focal length eq is beneficial for Olympus so that people can know what fov they get relative to 35mm which is a standard most people understand.

There's no benefit for Olympus to cite what f-stop would be needed on a comparable 35mm lens that gives the same fov and results on a 35mm sensor. It could make their lens/system look inferior even if it isn't, that's dumb marketing. Marketing wise you only cite your positives in comparison.

I am sure the AF system in MFT is much happier at F5.6 than that in FF at F11.

@RolliPoli: you've made the mistake of assuming equivalence is about equivalent exposures. It is not. Two lenses are said to be equivalent in this context because they gather the same *total* amount of light, not light per unit area (i.e. exposure).

Assuming your math is correct, your medium format lenses do indeed gather the same total amount of light as faster 35MM lenses and will produce images with similar DoF (if all other things remain constant). There are actual products on the market built upon this concept which compress a lens's image circle to a smaller format. The image circles become brighter in the process.

As mentioned already, the use of 35MM as the reference point is arbitrary. You could express any given lens in terms of equivalence to 6x7 if you like. All of the same concepts still hold true.

@RolliPoli I primarily use Olympus gear. I rented a Panasonic S5 and lenses, had fun with it. The equivalence basically worked out as expected. There was no magic, it was just two different sensor sizes doing different things.

GMT is a reference point. Greenwich Mean Time is not better than other times or some sort of superior time zone. But, if we want to have time zones and be able to reference, somewhere has to be the reference point. Usually whomever gets there first or is in power gets to set the reference.

You could use any format as your own personal GMT / reference point, it doesn't matter, doesn't change anything. In a sense I do that with m43, any product that looks interesting I convert to what kind of performance and results that would be like in m43, since it is what I use. We all do that with time, we say this or that place is behind or ahead of my time zone by this or that amount.

People get mad and defensive about the most random things, so weird we humans are.

OSPhoto I believe I was discussing focal length and aperture in the context of different formats. That was certainly my intention.
While I've always found discussing focal length 'equivalence' useful, this DPR humbug about aperture 'equivalence' is not.

When DPR's 'equivalence' is applied to aperture value it gives the impression that a lens gets slower on a smaller format.... f/4 becomes f/8 on m43 ...This is grossly misleading!
An f/ stop number is an absolute value that does not change with format whilst the difference in OOF area rendering between 35mm and m43 at a given f/ is minimal and, in any case, is a rendering or aesthetic quality that is not numerically quantified like a lens aperture value.

Most folks who buy M4/3 cameras, believe it or not, know what they're buying 😀. They've weighed up the pros and cons of the system and make purchases based on their needs and style of shooting. I've owned and used FF/APSC cameras/lenses but M4/3 is my system of choice because it suits me.

Maybe they are the ones who do not understand the relationships, all the details, or even the meaning of the word "equivalent". No one says it's identical or equal, when the word is used, e.g. to explain that 200mm in a M43 lens is equivalent to 400mm. No one claims the FLs are equal. That's in the context of FOV of the image (which is of course smaller and hence has less quality). 200mm is of course just that in a physical sense, not 400mm. People point out some equivalence mistakes should be careful, and make sure they are not showing their ignorance of the matter.

But it assumes 35mm film frame size is the basis for all comparisons. There a many, many formats and platforms, but your "equivalency" case assumes an arbitrary standard that has never been formally adopted, and can't be.

What about all those thousands who do not understand all the considerations of what they are buying into with the M43 cameras. They may well see the small size and the seemingly fast aperture and not realise that in combination with the smaller sensor that it actually limits some creative potential in terms of what one can do with blur. Equivalence might help them be aware that all is not what it might seem when comparing with say a Canon, Nikon or a Sony.

Equivalence is useful, so I don‘t understand the offence taken.

While equivalence is a very real thing, and is the only way you can compare different systems based on different sensor sizes, it is important to note which parts of it are most important for most shooters.

Most people feel that focal length and exposure equivalence are extremely important. There are a few who also believe that DOF equivalence is important too, but they are in the minority. It really just depends on how you do the majority of your shooting. If you are a portrait photographer, then you might want full frame, for the shallower DOF. If you are a landscape or nature photographer, you might prefer a cropped sensor, for the extra reach.

There is way too much fuss made about sensor size. You can shoot anything with any system. It is just easier to achieve some things with a sensor that lends itself to the things you need most. There is no best system for everyone. You just need to get whatever suits your needs best.

Actually the Panasonic lenses with OS are very slow ones with f/5.6 apertures. The Olympus lenses with OS are the 12-100mm f/4 and the 300mm f/4. With the 300mm f/4 on an EM-1 it is possible to shoot handheld at 1/8s and get sharp pictures.

The advantage of the Olympus is the combination of 5-axis image stabilization that goes back to at least 2015, and their full line of pro grade f/2.8 constant aperture lenses from 7mm to 150mm (full frame 14mm to 300mm) that are half the size and half the weight and half the price of DSLR or full frame mirrorless equivalent lenses.

" Actually the Panasonic lenses with OS are very slow ones with f/5.6 apertures. " -calson

The Panasonic 35-100/2.8 would like to have a word. The PL50-200 f2.8-4 also has OIS, as does the 42.5/1.7, so I dunno how you concluded only mostly slower Pana teles have OIS. The 35-100/2.8 in particular is about the same weight/size as this 40-150/4.

I'm not gonna wade too deeply into the equivalent argument but it's not very accurate, and lenses like the FF 70-180/2.8 reach a much higher performance envelope while weighing about the same as the Oly 40-150/2.8. There's unique and useful propositions in both formats.

Something like the 28-200 f2.8-5.6 is pretty comparable (if not better) in size and output to the 12-100/4 as well, tho not in build quality or IS, what the larger format doesn't have is something as tiny as the 14-150.

The 42.5 f1.2 has OIS too

The Panasonic Macro 30mm F2.8 has OIS too, the 12-35 F2.8 too.

PL45/2.8 macro does too, etc etc. Most Pana teles have OIS, period, regardless of speed. Heck even the PL200/2.8 does and that's one lens where I think they could've skipped it if they wanted to go as light or as simple as possible in the name of IQ.

The 42.5/1.7 is basically the same size and weight as the Oly 45/1.8 and has less field curvature so it's sharper into the corners, all that while having OIS and a shorter MFD.

I'm not knocking Oly because like I said before, for most people/bodies the inclusion of OIS at shorter <200mm FLs is no big deal, but Pana has often figured out how to squeeze it in with little if no drawbacks.

Olympus M.Zuiko Digital ED 40-150mm f/4-5.6 R Lens
$199.00
OM SYSTEM M.Zuiko Digital ED 40-150mm f/4 PRO Lens
$899.00

Well here lies the issue for most I would believe, is it $700 notably sharper? I know some folks just seem to throw money around on these camera an or lens like it's nothing, but that would be hardly the case for the vast majority.

On one hand, certain groups want to claim the gear doesn't matter while on the other, far less will public states that it does. I full well know that gear, does matter all other things being equal. Then there is the ongoing debate of case usage, for printing/digital. Either would be beside the point for me because outside of cost being prohibitive, I want the best possible lens.

It’s a nice lens, but one of my issues when I was with m43rds was the odd compression and flatnesss to images. It’s just physics I guess. Great system mind you otherwise..

Compression is a question of perspective which, in turn, is solely related to photographer, subject and background distances. A 300mm equivalent lens (on any system) gives the same 'compression' as a 300mm lens on FF.

There's no compression difference between systems.

If you want to convince yourself of Richard's point with your own eyes, YouTube "compression doesn't exist"

For birding, there's the low budget 75-300mm, "premium" 100-400mm and flagship 150-400mm TC 1.25 exotic for the most demanding shooters.

I constantly go over to the B&H site an monitor all the pricing/specs of all the latest MFTs offerings. I think they are one of the best concerning laying out specs an or the occasional snapshots from stated products. I would never spend $7,499.00 on any one Lens. Not even if I won the lottery.

It is MFT enthusiasts who seem obsessed with equivalence.

I shoot both formats and I it's not a controversial topic to me, but some people on both sides seem to take issue with it, I wouldn't generalize about either group tho.

Jonas: it’s easier to get shallow depth of field with full-frame systems because their lenses tend to have larger apertures. This is a well-known feature of larger-format systems.

Yes, but 99.9% or more lenses have adjustable apertures and it can be set to be the same as whatever it is on the smaller format which will give the same DoF.
Remember I was replying to this statement:
“Having full frame dof is not always ideal!” I think the author of that statement perhaps forgot that the aperture on most lenses can be adjusted.

I think he's right in some way.
You can for example get sharp images with a large dof with M43 at F8 but if you use F16 with full frame lenses they are usually already much less sharp at that focal range because of diffraction. Or let's say F11/F22.
I know, diffraction starts earlier with M43 lenses but it's not that much difference ... b

No one has said F4 is F8. We've pointed out that a 40-150mm F4 lens on a Four Thirds sensor is directly comparable to an 80-300mm F8 lens used on a 36x24mm sensor.

It's demonstrably true but you don't have to take my word for it.

It's far from idiotic.

Thank you Richard!

I wish more people here would substantiate their claims in such a fashion. Maybe we would have less recurring discussions cycling around the same poor reasoning.

^ You're very optimistic... :/ Stuff like that and DPR's articles which break equivalence down in simple and easy to understand ways have been linked here and elsewhere ad nauseam, and it doesn't seem to make much of a difference, hope springs eternal tho!

It's because it's a leapfrog metric over actual equivalence. Actual equivalence is exposure - not DOF equivalence or sensor light transmittance which is secondary to exposure. Those things are affected by other aspects of a systems performance - things like IS, or quality of optics, or sensor technology, or size considerations that don't factor into theoretical equivalence ideas. It's analogous to reviewing a leica M with a 135mm lens and comparing the equivalent frameline size to the viewfinder size of an SLR with a 135mm lens - it's a technical equivalence sure but it's smooth-brained because negates the strengths of the system for a narrow banded criterium.

/facepalm

"Actual equivalence is exposure"

So if that's what you think, why bother carrying around all that Micro Four Thirds gear?

You can go get one of the numerous 1" compacts and have the "Actual Equivalent" to a full frame 24-200 f/1.8-f/2.8 that fits in your pocket... or all kinds of other crazy options, like an Actually Equivalent Full Frame 24-600 f/2.4-f/2.8 that's a few inches long. Those things have IS, quality optics, good sensor technology too. I think things had 20MP BSI sensors before M43 did.

Take the same logic a step further... you can get a smart phone that's equivalent to a medium format camera with a couple of fast prime lenses. You have several camera modules with lenses that say Hasselblad on them, IS, advanced sensors and the exposure is of course the same, so it's all Actually Equivalent... I guess?

Why not shoot an 8x10 camera? Hell even 645 film is several times bigger than a 35mm digital sensor. GFX is bigger. 35mm is a piddly format in comparison.

This nonesense a about "actual equivalence is exposure" is just that. Why should a per unit area quantity control equivalence between different formats that have different areas? It's the antithesis of equivalence. It is exactly the opposite of equivalence.

For lenses we should ignore f/number. It is also a per unit area like quantity. Physical aperture diameter is a physical quantity that CAN be compared across formats, given the same field-of-view. And field of view is an obvious comparison across formats.

Beyond that image sensor performance is not even being factored in, where shooting at base ISO with plenty fast shutter speed is not an uncommon occurrence. In this state the bigger the sensor the better, with even lens equivalence no longer factoring in.

So what's the point of all this? It's about comparing different formats. Is what I have good enough? Am I missing something that can be offered elsewhere? Etc. Equivalence makes answering these questions easier.

"a 40-150mm F4 lens on a Four Thirds sensor is directly comparable to an 80-300mm F8"

Well lets define what the F number means:
"It is a dimensionless number that is a quantitative measure of lens speed"
https://en.wikipedia.org/wiki/F-number

"A lens with a larger maximum aperture (that is, a smaller minimum f-number) is called a "fast lens" because it can achieve the same exposure with a faster shutter speed."
https://en.wikipedia.org/wiki/Lens_speed

Doesn't mention anything about F number being a measurement of DoF.
So it would be more correct to say "a 40-150mm F4 lens on a Four Thirds sensor is directly comparable to an 80-300mm F4" Because the LENS SPEED is still F4.

The lens speed is still f4 but that f4 cannot be compared to f4 on a larger sensor.
f4 is a number that describes how bright an image will be at a given focal length. If you can't compare the focal lengths (because of different field-of-view), you can't compare the f-numbers attached to those focal lengths.

Therefore you are speaking nonesense. It makes 0 absolutely 0 sense to compare a m43 40-150 f4 lens to a ff 80-300 f4 lens. Just like it makes absolutely 0 sense to compare a f1.7 cell phone lens to any f1.7 full frame lens.

The only thing that is physically comparable across formats for lenses is the field-of-view and the physical aperture diameter. Comparing anything else makes no sense.

Kerensky97 - You really need to step back and read what people are saying. You're finding different ways to be wrong, but you're still wrong.

PLEASE READ THIS BEFORE POSTING AGAIN.

A 150mm F4 lens is a 150mm F4 lens. The f-number is what it is. It's a dimensionless ratio. It's not a measure of anything, per se. It's just one quantity divided by another. I've not written anything that contradicts that.

What I have said is that if I shoot a 300mm lens on a full-frame camera, stopped down to F8 it will take a photo that is essentially indistinguishable from the one I could shoot with a 150mm F4. This is provably true.

If you're happy to accept that a 150mm lens is equivalent to a 300mm lens (despite not being one) then it's equally true that the 37.5mm aperture diameter in that lens will end up having the same optical impact as a 37.5mm aperture would in a 300mm lens, which would be f/8.

...

F-numbers are not measure of speed any more than they are measures of depth-of-field. They are just a ratio, and one that relates only to the actual focal length, not the equivalent focal length.

The standard exposure model (f-number/ISO) relates to light per unit area. Which can make sense if you then think about enlargement to take into account the effect of viewing size. But is specifically designed to gloss over the impact of format size, hence works 'the same' across formats.

Equivalence takes enlargement into account by assuming a common viewing size, then helping demonstrate, rather than hide, the effect of format size. Images shot at equivalent settings have more in common than ones shot at the same exposures (not just DoF), because they are images where the same amount of light has been projected on the sensor, to describe the same scene and that's what the image is made up from.

Regardless of what someone's typed into Wikipedia, f-number has no direct connection to shutter speed: it's mediated through ISO, which assumes you care about how much light per sq cm your sensor is receiving, not how much light per portion of the final image your sensor is receiving.

It's not the only way of looking at the situation.

If I take an image on a 150mm F4 lens on micro four thirds, and one at 300mm F8 on full frame for the same exposure time, then both sensors will be exposed to the same number of photons. It doesn't matter what ISO rating is recorded in the EXIF: if you view them the same size, they'll have the same depth-of-field, the same diffraction and very similar tonal quality and noise. In most almost way they'll look essentially the same.

A 150mm F4 lens is a 150mm F4 lens. It is not a 300mm lens. It behaves like a 300mm lens on a different format. Specifically it behaves like a 300mm F8 on a different format, in that they take directly comparable photos.

"Don't get why everyone freaks out as soon as the word 'equivalent' is used."

Exactly. I myself am a M43 shooter (shockingly, to some people here). I'm perfectly happy with my f/7.1-f/11 equivalent zooms and f/3.5 equivalent primes.

In most cases there are no actual, existing equivalent full frame products of similar size and weight and other characteristics.

No big deal.

Sensor response is linear. Once you're above the noise floor, then it doesn't especially matter what part of the sensor's response you're in (so long as you stay short of clipping).

So if you increase the ISO to make up for the lower intensity, you get essentially the same result.

I've posted a link to a scientific journal explaining the maths, I've linked to an article with photographic examples, I've spent the last 14 years of my life testing cameras day in, day out and it's all consistent. I'm not forgetting or overlooking something.

The theory and the practice line up, repeatably.

And before you get into the complication of sensor and ISO performance maybe it's best to forget digital and imagine film at the respective sensor sizes.

If you take the photons hitting the FF sized film through a 37.5mm opening and focus the same amount of light onto the M43 sized film 1/4 the size it will expose 4 times faster.

Yes the performance of a M43 image with its less photoreceptors blown up to the size of a FF sensor will have less quality. Etc.

One of the byproducts of increasing the entrance pupil size enough to get FF 300mm F8 depth of field at M43 150mm, it's you're letting in about 4 times as much light. Hence the F4 speed, and 4 times greater ratio of light to the sensor.

Edit: Beat me to it. No M43s user cares about FF ISO performance. They just want a properly exposed image. Test it by switching your Nikon Z7 from FX to DX mode and tell me if the image is suddenly 1.5 times brighter or dimmer. Cropping the film to 1/4 size doesn't change the lens physics.

You still haven't read the article, have you? It literally covers this.

And whether you want to go into it or not, linear sensor response means that, so long as you're above the noise floor, it doesn't matter what digital number your exposure is recorded at.

The Raw data and the noise statistics of them will be essentially the same.

No one is saying the exposure changes when you engage a crop mode. In fact that article and several of my comments spell out that the standard exposure model is designed to work across formats.

But if I enter crop mode, zoom out to regain my framing, and view the image at the same size, then if I stick to the same f-number, it'll have different depth of field and more apparent noise than the full-sensor image (regardless of what that sensor size is).

Cropping doesn't change the lens physics but it stops you taking the same photo. To take a comparable photo you'll need to zoom out (and open up the aperture if you want it to look like the original)

Kerensky97:

I’ll try to explain this to you in a different way to the people above.

A photo taken at 40mm, f2.8, 1/100 sec, ISO 400 on micro four thirds will look the same as a photo taken at 80mm, f5.6, 1/100 sec, ISO 1600 on full frame.

The full-frame camera can take advantage of an extra two stops of ISO, meaning the lens only needs to be at f/5.6.

@Richard Butler… Why do you insist on opening the dreaded equivalency can of worms. Just review the lens as an m43 lens. No FF shooter is going to buy this, or I suggest, even cares.

It was a good overview until it became just another equivalency rat fight.

Richard Butle

I trust your next review of a full frame lens will also give the equivalence in MFT terms.

I personally would like to the see the next FF 35mm f1.4 lens reviewed have its true/real/equivalent aperture of f11 listed and highlighted several times in the review - as compared to a 250mm f11 lens for 8x10 format, obviously the gold standard format for imaging quality.

Have fun with your 35mm f11 lens sony a7 losers!!1

Those adverse to the equivalence discussion should stay out of it and leave the fun for those interested.

Again f/number depends on a physical measurement that cannot be omitted to compare physical lenses with different angles of view for different 'f'. A tiny cell phone aperture hole can never be equivalent to a giant full frame aperture hole, no matter how much the equality of f/numbers is repeated by the ignorant.

Also, ISO is a value calculated specifically to be usable across all sensor size formats, this is antithetical to comparing the snr across sensor size formats; It's the exact opposite of what you want. It purposefully obfuscates the difference between sensors for a whole image for the purposes of calculating exposure, a value by itself that has 0 use for measuring IQ.

This is not controversial. This is reality. Stop confusing yourself with equal numbers that are not comparable.

Where have I said F8 'is as fast as' F4?

I've specifically avoided using the terms fast or slow because they try to relative aperture value to shutter speed (via assumptions about ISO), which is the domain of the standard exposure model, which isn't what I'm talking about, as the linked article explained.

In the hypothetical scenario of going from shooting full-sensor to crop, yes, you'd have to either reduce your ISO or, if you couldn't, you'd have to increase your shutter speed, which would reduce your image quality by capturing less light.

If you're going to take a photo you need a camera and a lens. The sensor size (to a good degree) dictates which focal length you use. It's not unreasonable to consider both together. I've made clear that I'm drawing a comparison between this lens on a Micro Four Thirds sensor and a hypothetical full-frame lens on (all of) a full-frame sensor. I've explicitly stated that lens/camera combination in both cases.

The point is: the equivalent lenses will project the same number of photons during a given exposure time to the respective sensor format they're designed for. That's a property of the lenses, not the sensors.

The fact that most modern sensors perform extremely similarly, per unit area, means most cameras behave almost exactly as equivalence would lead you to expect. I'd probably be less equivocal towards the end if I re-wrote this piece today.

But I've not changed by position at any point. I've never said nor suggested that you could use the same shutter speed and ISO at different f-numbers on different systems, because the whole standard exposure model is designed to work across formats, by focusing on light per unit area. I'm not denying that the exposure system is internally consistent. It is.

But, per the article I linked to, equivalence gives a per-whole-image perspective, not a per-unit-area (exposure model) one. It means I'm worrying about what the final images look like, not what ISO value got recorded in EXIF.

I'd be interested to hear what photos you're taking that are so dark that they definitely couldn't be taken with a full-frame camera with ISO set two stops higher. There'd have to be almost no light at all to end up recording near the noise floor, but by all means link to one.

Two images made up from the same number of photons on two modern sensors (of whatever size) will look essentially the same when viewed at the same size (lens quality notwithstanding), regardless of what their ISOs are numbered as, Which is why it's meaningful to point out that two equivalent lenses project comparable amounts of photons to their respective format size, if given the same exposure time.

So far I've linked to a scientific journal article, explaining the logic. I've linked to an article explaining that it's an image-level way of understanding light, rather than the per-unit-area perspective used in the exposure model. I've linked to an article showing real-world example images.

I'm not sure what more evidence I can offer that might help you understand.

I happen to have the 40-150mm F2.8 and a FF lens that I can shoot in an equivalent manner (to demonstrate the effect, not because I'm saying anyone should ever aim to shoot in an equivalent manner).

Would a 150mm F4 image on Micro Four Thirds and a 300mm F8 image on Full Frame satisfy you that the two things are comparable or are you going to loop back to saying that the exposures are different?

It really is hard to take the stubbornness and failure to really think (I echo the request to read the very fine article linked, and think) of Kerensky97. You are wrong, and very clearly, and very obviously so. You make yourself look foolish, because you refuse to think this through.

"There are many users in the DPR comments who have said it's pointless to get a 150mm F4 lens on M43 because it's as slow as a F8 lens and you can't take pictures of birds in motion without them being blurry."

Where? I think it'd be a much better use of my time to try to help those people, but it's not something I've seen. I see people express a concern that it might happen, but not much of it happening.

Likewise I see people saying there's 'confusion' about equivalence and then misrepresenting it by saying it's only about depth of field.

I've not said that the lens is an F8. Equivalent apertures are also a 'measure of light' but light per whole image, not light per unit area. The article I linked to explicitly says that you shouldn't blend the two systems by trying to use equivalent apertures when thinking in terms of the standard exposure model.

But I'm not going to bring ISO into a lens article. Firstly because lenses don't have ISOs.

I'm purely re-stating the lenses physical properties on a common basis. The 37.5mm aperture diameter would be F8 if encountered in a 300mm lens.

We don't say it is F8, we don't say it's faster/slower, because that relates to the standard exposure model (within which context the f-number is used as a measure of light per unit area).

We say it's equivalent or comparable to an F8 lens on a different system (within which contrast the equivalent f-number is a measure of light per whole image).

We're not trying to tie it directly to specific cameras or sensors. It's not saying you should buy a full-frame camera and shoot it in this certain way. It's just stating the parameters in a way that is comparable across systems so that, in this case you can conclude 'actually, you can't get a lens this compact and flexible on another system.'

Yes, a shooter of a full-frame camera would have to raise their ISO (because we're talking about an F8 lens). It would give them essentially the same image when they did so but that too is rather beside the point.

We're not comparing it to another lens. We're comparing it to a hypotherical lens.

It would be easier if full-frame hadn't started to take off as a common format in digital, because then it would be clearer that it's just an arbitrary but universal reference point, not a suggestion that anyone is discussing specific cameras or alternative cameras.

No one is saying that users of one format should try to get the same ISO performance as another. It's merely explaining the circumstances in which you can.

It gets away from all the vague stuff about 'full-frame' is better (to some unspecified degree) at higher ISO because, er, maybe it has bigger pixels. It avoids the confusion that you somehow get more depth of field but at the same shutter speeds.

It can also help overcome the weird perception that Micro Four Thirds sensors have been underperforming, relative to other systems (they haven't, with the possible exception of dual conversion gain not being widely used yet).

But the fact that the camera has to change its ISO for your statement to work points out the fact that it's a bad comparison. Compared to:

"A 40-150mm F4 lens on a Four Thirds sensor is directly comparable to an 80-300mm F4 lens with a F8 depth of field."

Which is also true.
Factors in the fast shutter speeds you'll get from F4.
Also sticks to lens properties and doesn't bring the camera ISO into the debate (which I find funny considering ISO is one of your key arguments when discussing "Equivalence" but you refuse to address it when putting in an equivalence comparison).
And doesn't require an asterisk that says:
*This comparison is only applies if the FF camera is +2 EV either through ISO or Shutter changes.

@Richard Butler… What problem would it cause if you just didn’t bring any equivalence into the review at all? Just say it’s an f/4, 40-150 MFT lens and leave it at that. We on the Micro Four Thirds sub forum spent a lot of years trying to clean up these incessant “E” threads, and now here it is again.

I think the GMT example is a good one. When discussing something that happens in New York at 10am we don’t continuously feel compelled to always make sure we all know that it is 3pm GMT.

Reading through these comments, I'm simply not seeing FF users chiming in.

But yes, the M43 shooter who wants to say "I like my 150mm F4 because I can freeze birds in flight like a 300mm F4!" is likely to get some push-back, because they're stating something that's both seemingly true and increasingly meaningless the more you look into it.

For a start, focal length isn't part of exposure, so it's a logical fallacy to say 'like a 300mm F4.'

But the logical response isn't: "But your ISO noise is worse, so its like shooting F8!" Because that's a misunderstanding.

It's not 'like shooting at F8' because the full frame sensor is somehow better and therefore you can raise your ISO.

It's because both cameras are seeing the same view of the world through the same sized hole for the same length of time.

gary0319 - This isn't a review, it's merely a explanation of the products.

Some people still think in 35mm (film) terms when thinking about focal length, so I included that. But, partly because I don't want people getting the false impression that they're somehow getting a 300mm F4 lens, I made passing reference to the fact that it's F8 equiv.

But mainly I was trying to make the positive point that this lens plays to Micro Four Thirds strengths by offering a balance of flexibility and compactness that you don't get on other systems. No one makes a weather-sealed 55-200mm F5.3 for APS-C or a 80-300mm F8 for FF nor was there a 30-111mm F3.0 for the Nikon 1 system.

If you solely think in terms of it being a 150mm F4 and you only use Micro Four Thirds, just skim over the bit that expresses exactly the same thing on a normalized basis.

But I'm not going to miss out something that some people might find useful or tell half-truths to make my life easier.

Kerensky97 - This is my whole argument with the folly of using the aperture as a measurement of Depth of field.

I'm not. That's a misrepresentation.

By treating Aperture as a DoF measurement it throws off your entire settings for taking a picture.

I'm not. No one has suggested that.

Requiring all these addendums and asterisks about the differences that are inherent sensor differences.

Differences in sensor format. Differences between modern sensor performance tend to be minuscule.

You can't "equivalent" a Micro 4/3s and FF on that level.

You can. Repeatably.

bringing in sensor shortcomings into a lens comparison over complicates things.

I'm not particularly bringing sensors into it and I'm not sure what sensor shortcomings you mean. If anything equivalence shows that the sensors in recent Micro Four Thirds cameras perform as well as those on other systems.

None of this is about how anyone shoots. It's just a way of describing the lens behavior on a common basis

@Richard Butler …I was just hoping you might make make my life a little easier by not having to dig through all this old school equivalence minutiae. But you are right, I should have stopped reading at “f/8”. Good advice.

gary0319 - I thought that testing and explaining the theory would stop the arguments, because its provable and helps prevent all sorts of misundstandings. It can be a hugely informative way of understanding the tradeoffs and strengths of all systems

I thought that a simpler article making clear that equivalent and exposure are different perspectives and you shouldn't muddle them up would help reduce any confusion.

But I'm not sure how much genuine confusion there is, at this point (I try to stick to responding to people who actually seem confused).

I'm not going to be cowed into lying to our readers because a minority has decided that it's an attack on their system of choice. It's not.

"Differences between modern sensor performance tend to be minuscule."
So then why redefine F-stops as mainly a DoF setting* when it forces you to factor in ISO changes and how the two sensors handle ISO?

Just keep it simple and not bring ISO or sensor performance differences into the lens equivalency in the first place, if you're going to bring up LENS equivalency at all.
"A 40-150mm F4 lens on a Four Thirds sensor is directly comparable to an 80-300mm F4 lens with a F8 depth of field."

*If you change the ISO. Then exposure will be the same again, which is ok because Full Frame ISO performs better than comparable Micro Four Thirds ISO.

Differences in performance a minuscule on a per unit area basis, and hence they perform in proportion to their format size if you look at a whole-image level.

But, AGAIN, I'm trying not to bring cameras and ISO into this. This is purely about the fact that a 150mm F4 lens projects the same amount of light onto a 17.3 x 13mm area as a suitably large 300mm F8 lens does onto a 36 x 24mm area over the same period of time. That's all I've said, and it's true.

Light is the stuff photos are made from. It defines depth of field, level of diffraction, and photon shot noise experienced by the sensor.

If you choose to take it further, and compare cameras, then you can. The point is the difference in ISO performance isn't coincidental. The reason a full-frame sensor will offer near-precisely two stop better ISO performance comes from the fact that both sensors are experiencing the same amount of light per whole image and modern sensors are very good.

This avoids the fallacy of there somehow being a depth-of-field advantage to one system over another. It helps show that it's format size, rather than pixel size that has most impact over whole-image noise level. It also shows the direct 'more light/better IQ/shallower depth of field' relationship: if you're shutter speed limited you can't get any extra light for better IQ without having to accept shallower depth-of-field.

They're all interconnected, so I'm not going to mislead the readers by saying it's just depth-of-field. It's not.

Kerensky97, do you not find the projector analogy helpful:
Project to 60", observe the brightness, move the screen back so that the same exact image is 120", the image is now 'underexposed' by 2 stops.

This is equivalence: The projector lens is equivalent to itself. The aperture area did not change. The field-of-view/image did not change. The light going through the lens did not change. Nothing changed except the image size and the perceived brightness. The image is the same. The "lenses" are equivalent.

Richard Butler:

Thank you for the incredible patience you have shown in these comments attempting to educate some readers about equivalence.

Personally, I find a quick mention of equivalence during lens reviews to be useful.

Please continue to do this.

People who do not find equivalence to be useful are under no obligation to use that information.

"This is purely about the fact that a 150mm F4 lens projects the same amount of light onto a 17.3 x 13mm area as a suitably large 300mm F8 lens does onto a 36 x 24mm area over the same period of time."

See, I think we're arguing semantics until you make a comment like that. You need to recheck your math.
Like you said earlier f-number(n) is just a ratio of focal length(f) and aperture diameter(d). N=f/d
So the front element of the 150mm F4 = 37.5mm
The front element of the 300mm F8 also =37.5mm
Same amount of photons coming in over the same period of time.

But the M43 150mm lens is focusing those 37.5mm worth of photons onto an area 1/4 the size of the 300mm lens. Having 4 times the photons hitting the sensor makes a big difference in exposure times.

The fact you keep glossing over this is kind of alarming. Maybe it would help to just consider the size ratio of front element to sensor size. That 37.mm front element is massive compared to the M43s but not as big next to FF.

And the m43 guys always say the FF guys bring up the equivalence arguments.

Ok, glad we are getting somewhere. Let's develop our agreement:

So say you have a 20mp FF sensor. You also agree that each pixel would count identical number of photons for f/8 lens vs f/4 m43 lens and the same image/field-of-view on a 20mp m43 sensor.

If so, now we get to the part where we realize that the equal counting of photons translates to different per-unit-area sensitivities needed for proper exposure.

The photon counts are identical but the ISO used to get the same exposure on each is not (here iso is essentially a fake quantity that just makes exposure math work out). If the pixels have the same noise floors they will still take the same photo with the same number of photons at each pixel.

Did we diverge anywhere or are we still following each other?

After reading thru this I can only /facepalm again tbh.

M4/3 has some pretty unique teles and equivalency only reinforces that, it's not an indictment on or slight of any format. Other than the original slip (since corrected) in the way the 12-24 comparison was worded I thought Richard was spot on.

At this point if you're really gonna try and debate why 35mm equivalency is used as the defacto frame of reference (and that's all it is), well, you're gonna die on that very hill. Carry on...

No. We are not talking about sensor performance.
We are doing a geometry exercise where each pixel on both sensors has the same view frustum of the aperture, just like in the projector analogy.

Photon counting is not meant to employ the sensor. I'm just demonstrating that each pixel gets the same amount of light, just like how each giant pixel on the 120" image gets the same amount of light as each pixel on the 60" image.

Im controlling for all variables. I'm explaining to you why exposure is different but also meaningless.

If your photon counting pixels on m43 and ff all get the exact same answers, all 20 million of them. How is that not equivalent? The sensor here is only demonstrating the same light for the same image. I'm not talking about ISO performance.

Now where did we diverge in thinking? Can you explain how every view frustum division sees the exact same thing is not equivalent?

"Lets eliminate the sensor performance debate completely so it's just a LENS equivalency scenario."

There is no such scenario. Nobody uses lenses without cameras. Equivalency is about getting *equivalent photos*. That is simply the definition of "equivalent" in this context.

As for your film exercise, you push the larger piece by two stops, but then you enlarge the smaller one by a correspondingly greater factor to get the same size print. Both steps increase grain/noise in this hypothetical film so that you end up with prints that look more or less the same in the end.

@gary0319, "What problem would it cause if you just didn’t bring any equivalence into the review at all?"

I have to disagree . The equivalence talk actually helped me a LOT when I got into ILC photography. I have mainly Olympus gear, but I am not loyal to any brand, no reason to be, just cameras, I just like pictures and whatever can get me the ones I desire.

I think there can be an assumption by seasoned photographers and forum members that everyone reading articles or posting on forums are experienced and or versed in photography and gear knowledge.

That's not the reality, and I believe the articles should give information for both the experienced and beginning photographer.

Understanding equivalence is very helpful for people looking to make purchasing decisions and for people who have experience in one system, but don't actually understand all the stuff with sensor sizes, etc to have an idea of what they can expect from a lens or system.

When I first started in the ILC world, I personally did not understand that there was a difference between the results you get from a certain f-number lens vs the same one on different sensor sizes.

I had experience with my 1-inch, and with a friends APSC, but truly didn't know why the APSC could get better pictures in certain situations despite similar f-stop settings. I wasn't into all the nitty gritty, I just took pictures.

After I got my first Olympus camera, the E-M10 II + kit lens, I still didn't fully get it I started comparing the two cameras and seeing that things weren't really the same, and also that my 1" outperformed my large camera with a kit lens in some situations.

Reading about equivalence including in articles about lenses on this website as well as others actually helped me better understand what my cameras strengths and limitations are.

I would imagine there are other people in the same boat as me who also are and will continue to benefit from that.

I agree with OSPhoto and would make the point that it’s not just novices who don’t understand equivalence, given some of the comments in this thread.

You can't be serious. Speedlights are only useful in a limited range of situations.

It’s pretty naive to think that every photographer can setup every shot in every genre of photography.

Try shooting events. Sports. Try shooting wildlife. No doubt you can put yourself in position where the light is more favorable. Sometimes. But sometimes the action is happening where it’s happening and the people are facing the way they’re facing. And you can’t tell the animals to turn around and face you because the light is better this way.

Sometimes photographers can use speed lights and setup their shots. Sometimes they have to capture what’s happening wherever it’s happening with whatever light is available.

I will till the end of days use equivalency to understand what to expect optically when thinking about using other systems. If you find that to be idiocy so be it, I call it taking the blinders off and exploring other formats, I could care less if you ever get it or not, my guess is when you shoot with a different system you wing it, real pro.

@Impulses
You are most likely right about it. Looks like the move was driven by the competition, all about the IP53 rating. It gives OM an upper hand over Panasonic in terms of water resistance.

I only use MFT, never used (for longer than a few hours to try it out) other formats. I couldn't care less about equivalence. I know my equipment what the limits are and what the gains. And yet since 2010 when I started photography with the E-PL1 I see all kind of non MFT users battle over it in all MFT related articles. It quite pathetic actually and reminds me of the SEGA Megadrive vs Super Nintendo discussions at my primary school.

I don't know of any M43 user who worries about ISO performance when they think about equivalence. M43 users know that a smaller sensor isn't going to perform like FF. The attitude of FF saying "Your sensor isn't going to be as good so it's not equivalent! seems like needless pixel peeping or worse, bullying.

M43: "I want to take a picture like this 50mm f/2.8 shot. So I'm going to get a 25mm f/1.4"
FF: "You have to change your ISO because your M43 will have more noise than full frame!"
M43: "I don't care about noise, I know I have a M43 sensor and it's limitations, I just want to take a picture that looks about the same as far as angle of view and DoF is concerned."

I'm a M43 user. I worry about ISO performance when thinking about equivalence. Those two stops make a significant difference if I'm shooting a concert or something like that. In that situation it's not even so much the noise but the dynamic range, which also takes a hit when increasing ISO.

The whole point of equivalence is equivalent photos. Noise and dynamic range definitely figure in to it. Yeah, we all know smaller sensors perform worse than big ones. Equivalence quantifies this and tells us to what extent.

Because equivalence takes into account the fact that most people's computers show the images at the same size, regardless of the format size they were captured on, which wasn't the case in film, where you had to think about the enlargement factor.

This has been explicitly addressed

For consistency, can dpreview list equivalencies with every known format sensor/Media in every single article? I'd like to know equivalent of all FF sensors especially in relation to x-pan film and gfx cameras.

gavinIg - in principle you could (equivalence doesn't favour any format, the implications of physics work out the same, regardless).

But, just at as we do when writing about the 44x33 format used but the GFX, X1D and digital Pentax 645 cameras, we make reference to the 135 film format, because that's the industry standard. Olympus, Panasonic and OMDS also use it as their standard reference point.

B&H lists 35mm equivalency for every other format btw, right on the specs page. 🤷🏻‍♂️ You'd be surprised how often newcomers to photography ask about it, you probably don't see it as much here because everyone is super aggro and will bite your head off but I see new APS-C shooters confused about the FL equivalency all the time on Reddit etc.

Well B&H only lists the focal length equivalent, so kinda the way manufacturers like to do it. Also I don't think crop factor is only something where newcomers struggle from time to time. For MFT it's easy because it's just x2 but it can get a bit more complicated. The LX100 has a MFT sensor but a crop of like 2.2 in 4:3. Stuff like the Blackmagic Pocket Cinema Camera has a crop of like 2.9 or something. The GH5s a crop of 1.8 in video. Nobody can tell me they can keep track of the crop factor for every format or camera out there. I wouldn't know the 1 inch sensor crop from the top of my head since I don't own any currently, but that doesn't mean I wouldn't consider one and read reviews or hands-on.

"Because equivalence takes into account the fact that most people's computers show the images at the same size, regardless of the format size they were captured on, which wasn't the case in the film, where you had to think about the enlargement factor."

It is the weakest comment I have ever seen from Richard Butler.

Plenty of people printed their images at the same size from different formats. At least I did on my Canon IPF5000.

I still have my Leica P600 with its tiny "Full Frame" projection area and ancient Kindermann 6x6. If I ever am going to project my slides on my 6-foot screen - I will use the width of the screen regardless of the format.

And of course, in the film era, everybody knew that MF or LF gives better ultimate quality. But nobody spent so much time in every thread about using 35 mm film proving MF or LF is better.

Pana has updated numerous lenses with weather sealing and even mildly tweaked mechanics at times, they started around 2017 and have kept updating lenses here and there thru 2019 or 2020 (I think I bought the PL25 II when it came out in 2019). I wouldn't make too much of it...

The 100-300 II got a major update in it's aperture mechanism that allowed it to keep up with modern bodies whereas the first version wouldn't even do 10fps (and an OIS tweak too IIRC. Updates to other Mk II were milder, I think the 35-100 II was mostly a cosmetic update to get rid of the outdated HD labels and some tweaks for video.

Oly has updated the aesthetic of other zooms in the past, improved weather sealing should be more involved (specially if they're meeting that IP53 or w/e) but still...

Richard, I am unsure and have no information that Olympus' would manage 2 parallel versions in the production line. My assumption is that the II replaces the first version. Wet the work to make the lens better sealed I am not quite clear on the exact difference since the first version was not specified. Hence, I do not know how much actually needed to be changed to make the lens compliant with a specific water resistant classification. Further, I assume that the warranty doesn't cover you if the lens malfunctions due to water damage? If OM were to replace or repair any lens damaged due to water and they would need to prove that it was subject to greater water exposure than the guarantee to not honour the warranty then that might be worth something. This is rarely the case though.

I saw a 35-100 f2.8 going cheap recently and nearly bit. Then I thought the 45-175mm may be the better travel/landscape lens. If I want sports/action I have that covered with A9 and 70-200 f4.

The PL50-200 would be my ideal single tele lens travel solution, if it wasn't so pricey. I had the 35-100/2.8 already when it came out *and* I'd been using my 42.5/1.7 & 75/1.8 primes more than the 35-100 anyway... So I settled for adding the 100-300 II.

The PL50-200's range seems like the most ideal all around-er for me tho, specially since it's compatible with TCs (even tho Pana still doesn't make it easy to buy them in the US) and it's no larger than my 100-300 II, but range preferences are pretty subjective. If I'm going longer than 100mm (200mm EFL) I tend to wanna go much longer.

I might sell my 35-100 & 100-300 if Oly ever comes out with a cheaper xx-2xx competitor, specially if it adds a tripod foot... I'm kinda getting back into using the 35-100 on my smallest body tho, and I did get it relatively cheap ($850 + $100 gift card IIRC, before mk II came out).

Sony has pretty much suspended all production of their APSC lineup while Canon's users are pretty much in limbo about theirs.

Meanwhile, both Pana and OMD Solutions has just released two outstanding products for MFTs along with Lens as of late. So yeah, maybe FF is all that is left these days to really compare to.

So I don't get slamming Richard on this article for comparing equivalent to FF nor anything other format. There literally nothing aggressive about this article.

I'm pretty sure we regularly state the equivalent aperture values for APS-C lenses and I know I've describe the Nikon 1 32mm F1.2 as being ~85mm F3.2 equiv. Look at our more recent compact camera reviews, you'll see they have diagrams plotting equivalent focal length against equivalent aperture. It's not just something we do for Micro Four Thirds. But the 135 film system is the standard reference point used by most photographers (and manufacturers, including Olympus, Panasonic and now OMDS).

It would be misleading to state that a 40-150mm F4 is equivalent to an 80-300mm without acknowledging that it's not equivalent to an 80-300mm F4.

In this case I tried to be the opposite of provocative: I pointed out that mFT allows a balance of size and flexibility that other formats don't offer. But the best way of making that point is to compare on a like-for-like basis. I'm not going to avoid the obvious way of making that comparison because a handful of people are inexplicably opposed to it.

There is no such thing as “f/8 shutter speeds”. You are free to use any shutter speed you want regardless of the lens.

Kerensky97 - There is no debate. There's an established, mathematically and logically rigorous system for comparing the potential of camera lens combinations across (any) formats, and there are a handful of people who demand that it mustn't be mentioned because they are worried it somehow disparages their system (it doesn't).

As has been pointed out, if you can shoot an image at 1/200, F4, ISO 200 on a Micro Four Thirds camera, you can shoot an image that will look essentially the same at 1/200, F8, ISO 800 on a hypothetical full frame camera.

Those two images will have more in common (DoF, diffraction, noise) than two images shot at the same exposure values (matched EXIF data).

The last MF review I read on DPR had several comments about equivalency to FF, people didn't seem up in arms over it. /shrug

Richard, when you say " I'm not going to avoid the obvious way of making that comparison because a handful of people are inexplicably opposed to it", you miss the point. Nobody is opposed to comparing parameters across various systems when it is warranted. However, you used the depth of field disadvantage of larger sensor systems (at the same aperture and angle of view) to disparage the smaller system and you did it by saying nobody makes f8 lenses in the arbitrary larger format. By doing so, you deny your reader the chance to consider that they could be comparing to a number of 70-200/4 lenses (which could give the same reach per pixel) or stalwarts like Canon's 70-300L which is highly comparable in function, though vast. It is provocative and negative.

You should take on board that you will upset very reasonable people if you tirelessly continue to push your depth of field barrow with that bias. We all know about equivalence. So please put it to rest unless warranted.

There is no depth-of-field advantage or disadvantage to any system because there's no reason to use the same f-number across systems. As photographers surely we're choosing the f-number that gives us the DoF we want, not picking arbitrary numbers and sticking to them?

My point wasn't disparaging: it was saying that there aren't lenses that offer this combination of size and flexibility on other systems. I used FF in this instance because that's the usual reference point but I could, equally have said there are no 55-200 constant F5.6s for APS-C and it'd be just as true (but I'd then have to stop and explain where those numbers come from).

It's not negative and it's not intended to be provocative. And there's nothing to stop you comparing it to 70-200mm lenses if you like, but it won't give you comparable image quality, so that's not going to be a reference I make.

Pointing out that a lens offers a set of properties you can't get elsewhere is a good thing, surely? That's the point I was trying to make: that this lens offers a balance of size and flexibility you can't get elsewhere. That's a benefit, not a dismissal.

And, as I say, if I'm going to describe the equivalent focal length, it would be imprecise/misleading to leave the impression that it's comparable to an 80-300mm F4, because that is not true. And it's just as misleading to say I'm talking about depth of field. I'm not.

It was kind of you to reply, Richard. I really wish you could understand how sick and tired a lot of us are about the pointless "equivalence" bickering and how needlessly putting it in your article is provocative.

The reason it is provocative is that we can avoid reading the comments but, when it's in the text, the only way to avoid it is to not read the article. Ironically, we know we won't get it when the article is about a less common digital format (35mm) but we will get it when the article is about the popular APS-C or 4/3 (or even one inch) formats.

Also, if you want maximum image quality (=base sensitivity) and the same shutter speed, you WILL be using the same f stop...

But that maximum is higher, so it amounts to saying that to get better quality requires sacrificing either DOF or shutter speed, which is exactly what equivalence says ( https://doi.org/10.1117/1.OE.57.11.110801 “In principle, the larger format can only provide a significant step-up in IQ when utilizing its extra photographic capability, i.e., when equivalent settings do not exist on the smaller format.”)

But no one forces you to make that sacrifice (the larger format only offers the *possibility* to do so), so there is no intrinsic DOF advantage or disadvantage: you can get similar quality at the same DOF and shutter speed.

@deep7

When it's in the Text, Richard is merely doing his job. When it's in the comments, folks can literally go either way, an some will, depending on how the argument has been shaped. I shoot almost all the formats other than MF. I have never found pointing at "equivalence" to be pointless.

Someone pointing out "equivalence" in an article is actually supposed to be standard procedure. Not everyone reading an given article already knows an given "equivalence". Ironically, I am always seeing "equivalence" talked about on various sites an I have never had any problem with it. Nor have I seen when it's been talked about on this site other than this format, seen such an huge claim of provocation.

It's gets really odd when when we move to MF, because things start to reverse. So yes, we need to keep those things in articles. Regardless of format.

FUJIFILM GF 32-64mm f/4 R LM WR Lens

25-51mm (35mm Equivalent)

Or the Hasselblad 80mm F1.9, for the 44x33 system, about which the company says (quite correctly):

With unique twin AF motors and outstanding optical design, this lens provides an equivalent aperture of f/1,5 and a field of view similar to 63mm on full frame 35mm systems.

deep7 - I'm not putting it in the text to prompt bickering. I genuinely don't understand how it's even contentious, given it's a readily provable fact.

The point is that plenty of people do still think in terms of 35mm equivalent focal lengths, so I'm not going to skip that detail. At which point, I'm not going to help propagate myths that you get behaviour equivalent to a 80-300mm F4, because you don't. What you do get is a camera/lens combination that's more compact and flexible, as a result. That's a good thing and that's all the article says.

Deep7: if you’re sick of the bickering around equivalence, then stop bickering!

All of the bickering about equivalence in these comments has been started by m43 users who either don’t understand equivalence or object to the reality that it’s a useful point of comparison.

Good call. The black version of the 75mm 1.8 Oly is my favourite. Especially on the EM-5/10 bodies.

the 12mm F2 is a thing of beauty... especially on a PEN-F

and pdelux - that 12mm f2 with pen F is such a small sharp little combo - Hopefully some of the new tech will dribble down to a pen F mk2. OM would have another hit on their hands imo!

Well then they need to also calculate it and write it down for other lenses just like for m43 lenses. "80-300mm lens on full frame (and an aperture diameter equivalent to F8)." They should also do this for e.x. an APS-C 12mm F3.5 lens (what is the aperture diameter equivalent to?) and a cellphone 4mm F1.4 (what is the aperture diameter equivalent to?) lens.

Good one Photomonkey. We pros agree with you. There will be exceptions but they are in the minority.

If you don’t care about noise then ignore the equivalent numbers. For those who care, they are useful to have. But note that “Noise is a non issue in the ranges people use up to 3200ISO” is kind of a circular argument, since that range can apply to a wider range of conditions with a faster lens.

" Why do some MFT users take it as a slight against the system?"

Because usually it is obviously intended as such.

You honestly think MFT users need help to figure out what f4 means on their camera? People are providing a service to them by always pointing out FF equivalence?

It's not intended as a slight and I mention it explicitly to make the point that there aren't lenses offering this combination of size and flexibility on other systems.

But I'm not going to state that it's an 80-300mm equivalent and pretend that makes it an 80-300mm F4 equivalent, because that would be misleading. So my choice is: omit the equivalent focal length range that's used as standard across the industry or give the full picture and have a few people take it as a personal insult (even though it doesn't even disparage anything).

Lenses and cameras are just a tool.
Still, creators want what they want.. (as I go grab a full set of black diffusion, glimmer glass, soft FX, ultra cons... tobacco filters for a bank commercial lol)

Why would it mean that it takes slow blurry photos in low light? Any lens can be used with any shutter speed that the camera is capable of.

@richard butler, But I'm not going to state that it's an 80-300mm equivalent and pretend that makes it an 80-300mm F4 equivalent“ I’ve got a light meter that disagrees.

No it doesn’t.

The Mad Kiwi: where are you putting your focal length into your lightmeter?

A 40-150mm F4 lens is an F4 lens. Your light meter works as designed.

It'll give images equivalent to a 80-300mm F8 lens on full frame, this can be proven mathematically and with images. Your light meter tells you nothing about how your lens or camera relates to other lenses and cameras.

As you imply, focal length has nothing to do with exposure and your light meter doesn't have an opinion about focal length. In terms of exposure, this is an F4 lens, because it's a 40-150mm F4.

You either have to work in per-unit-area exposure, at which point, when you zoom in to 150mm, you have a 150mm F4.

But as soon as you invoke an comparable lens on another system by calling it '300mm equivalent,' it's only honest to acknowledge that it's not behaving as a 300mm F4 equivalent lens. (Which can be proven by shooting a virtually identical image with a 300mm lens on full frame, set to F8)

Cameras work as designed: within the standard exposure model, which no-one is contesting. But you can't mix and match and claim the best of both worlds.

Sure you can find low-tier plastic stuff for FF in this size class, but the 40-150 is a pro-grade lens.

Hank: "Quite simply there aren't any 80-300mm F8 lenses for full frame on the market, so there's no way to match the size, weight and range that this lens brings. Our initial impressions of the lens's characteristics are also extremely promising, with it appearing to deliver sharp results, even at close focus distances." - Richard Butler

Comparing old 80s lenses to modern digital lenses just doesn't work. Everything was tiny back then compared to now.
There is a big modern size cost to having less distortion, better out of focus rendering, faster quieter AF motors, digital communication, stabilization, weather sealing, etc.

Impulses: "I'd be curious how well those hold up at 42-61MP" -- not great... which is often better than the very best MFT lenses have ever done. ;-)

Unfortunately for smaller sensors, easy-to-get lens resolution in lp/mm is largely independent of lens format. My 28-200mm (which is surprisingly sharp, although it has other optical issues) is delivering about 20MP of scene resolution on FF, which means about 8.5MP on APS-C. However, A FF sensor is nearly 4X the area of an MFT sensor, so my 28-200mm would only project about 5MP of resolution on an MFT sensor. Excellent MFT lenses tend to come in at around 6-7MP; only one that DxO tested reached 16MP (on a 20MP sensor).

The moral of the story is small sensors make a lot of things harder. You do get some advantages, such as it being easier to avoid having IQ drop off in the corners of a smaller sensor format. However, it's starting to look like getting acceptable resolution on MFT cancels any size reduction one might have expected....

Old lenses are small because they barely correct for anything. My old Olympus 50mm 1.4 is pretty small and light compared to even some newer 50mm 1.8 lenses but you need to close it down to like f2.8 to be even barely acceptable by todays levels, while with basically any modern lens from the bigger manufacturers you don't have to worry about stopping down unless it's for DOF control or in some really really specific situations. Sure many do sharpen up a bit towards the corners, but with most older lenses the difference between wide open and 1 or 2 stops down is like putting vaseline on it and not.

" However, A FF sensor is nearly 4X the area of an MFT sensor, so my 28-200mm would only project about 5MP of resolution on an MFT sensor. Excellent MFT lenses tend to come in at around 6-7MP; only one that DxO tested reached 16MP (on a 20MP sensor). " -ProfHankD

I've always had some issues with the way DxO tests and abstracts their results (why do some lenses test differently on bodies with the same sensor or the same res?), but I respect your opinion a lot and you'd probably understand it far better than I.

That being said, the older 12-40 that the new one is based on tested at 12MP on the E-M1 III didn't it? Unless I'm reading it wrong, and there's plenty of lenses as sharp or sharper than that zoom... The 75/1.8 seems to say 15 and the 35-100/2.8 (which I'd expect to be roughly in the same class as the new Oly 40-150) says 13...

The 20/1.7 pancake is right up there with the 35-100... Seems there's more than a few that can do far better than 6-7MP, what am I missing?

There *are* far smaller bodies than the OM-1 y'know (and I now you know, I recall you rightfully complaining about the EFCS limitations on Pana's smallest bodies!)... The day I can get a FF combo as small as my GX850 + 75/1.8 I'll be all over it, heck I'd settle for a modern AF ~135/3.5 that can resolve well on high res bodies.

By the same token I started shooting FF when I realized quite a few recent and AF (and faster by equivalence) FF primes going from UWA thru normal were just as small as some of my M4/3 ones (eg SY 45/1.8, 24/2.8 G, 20/1.8 G, even the 35GM isn't that much larger than my 17/1.2, tho heavier).

(continued) There's plenty of combos that can be cherry picked on both formats to make either one look out of whack or larger/smaller. What's the "top quality" 6-7MP M4/3 lens you keep alluding to btw?

Just curious, the ones I looked at and listed above (cherry picked out of self interest!) seemed to do far better so it seems lopsided to conclude that most excellent lenses only resolve half as well.

" Impulses: Again, the AVERAGE MFT lens reviewed by DxO gets 6-7MP -- half are worse, half are better... " -ProfHankD

No offense but that reads very different from the qualifiers you originally used, hence my confusion, sorry...

" **Excellent** MFT lenses tend to come in at around 6-7MP; " -ProfHankD

" Impulses: Yes, 6-7MP is DxO's (generous) rating for an "average" **top-quality** MFT lens (DxO didn't review lower-end or 3rd-party lenses); " -ProfHankD

**emphasis added by me...

" (DxO didn't review lower-end or 3rd-party lenses) " -ProfHankD

Where are you looking? Maybe I'm looking in the wrong place but I actually see more low end M4/3 lenses on their site than anything, there's 2 Oly Pro lenses and the 75/1.8 (which I'd throw in with the Pros) and like 10 decidedly lower end non-Pro lenses, plus the macro and some old 4/3 stuff.

Similar story for Pana, there's the Nocti and the two original f2.8 X zooms, plus a PL macro, but most of the other stuff is decidedly lower end.

(continued) If the average is drawn from those then it's skewed towards lower end lenses. They might not be priced low by the standards of vintage stuff, but they're pretty cheap by today's standards.

" BTW, the A7 is not even close to being the smallest FF body. Sony's A7C is MUCH SMALLER (although not lighter) than the A7. ... Incidentally, the GM1 is about the same size as my Pentax auto 110 SLR, and even thinner -- but the lenses for the Pentax are TINY compared to MFT lenses. ;-)" -ProfHankD

It's a hump-less A7... ;P I really dig the concept but idk that I'd call it *much* smaller, definitely lighter tho. I still own a GM1 myself and the much more recent GX850 is way closer to it than to any other ILC, I actually found it a useful upgrade over the GM1 in a whole bunch of ways. I hope Pana revives either model line and that Sony puts the A7C back into production.

@impulses -- you used other factors outside of "equivalence" to make your comparisons which are valid, and important to you. That is not what I am talking about. I'm referring those who use purley equivalence numbers without considering the other areas - as you did.

The point is -- equivalence tells you only that the image characteristics are "similar" (DOF, Noise, FL/AOV). It doesn't tell you how good the image looks. It does not solely predict how heavy, or what a lens should cost and how valuable it is to a specific user. It also doesnt tell you the resolution, rendering, OOF characteristics etc, build quality, weather resistance, Focusing speed etc.

Just as there is on the same format -- there are lenses which costs 3, or 4x other lenses with the same FL and Aperture, and they exist for a reason.

Indeed, it's the lens that's long been needed to fill the gap between the tiny and surprisingly decent 40-150f4-5.6 R and the larger and expensive 40-150 f2.8 Pro.

It fills the gap well on both size and cost. I really wish it had been available when I was still shooting m43.

I think it's nice but it's not a revelation, there's been other xx-150 lenses and we also had the similarly sized 35-100/2.8 (which now runs less than the 40-150/4 will)...

TBH I find 150 (or 300mm equivalent) to be kind of no man's land, I know that's totally subjective but it's not long enough for wildlife or super compressed landscapes (would want 200mm / 400mm EFL for that) and for more mundane landscape duties or events the 70-200 equivalent range is enough.

I'm more interested in the two xx-2xx Pro teles Oly had on the roadmap, it's weird that they've never made anything in that classic range (it's equally weird that it took so long for Pana to revisit it with the PL50-200 but anyway...).

OS: 50 f/2 please. 35-100 is too short a lot of the time. The extra FL will allow me to leave the 40-150 f/2.8 in the bag/car/home most of the time. Unless I need a TC or f/2.8, it saves me significant weight, especially for an all-day carry shooting handheld. I'll feel much more comfortable I have all the range I need when I can zoom out to 150. For the additional cost and weight an excellent compromise for speed when I use this FL outdoors most of the time. 40-150 keeps me in the system. I feel like OLY/OMS understands the value of the extra reach like no other system does.

@OSPhoto: I've used the 35-100/2.8 plenty on an E-M5 II & III and I've got no complaints with the mix, original one, bought it on a whim for like $850 + a $100 gift card before the mk II came out... Although these days I've been using the 42.5/1.7 + 75/1.8 combo more often, still glad to have both/all.

The Nikon Z 24-70/4 Richard linked is the closest thing to it, weather sealed with fast AF and not much bigger at all while being a stop faster (tho noticeably heavier and possibly more fragile since it uses a collapsible design)...

OTOH if you don't care about the speed at all you can make the argument that something like the tiny Nikon 24-50 or Sony 28-60 can achieve similar performance in an even smaller package than the 12-40. There's room for all of it in the market IMO.

(continued) I think teles is where M4/3 has more of an edge and more room for differentiation tbh, most FF teles are far larger and other than the very cheapest consumer 70-300 they start at like 800g+ with a couple (literally) around 600g, that Canon RF 100-400 is one of the very few exceptions... Tho I wouldn't say it has a similar range as the 40-150.

A crop of the long end of that Canon on a high MP body will be more comparable to the Oly 75-300 than to the 40-150... And it's priced and sized more like the 75-300 or Pana 100-300 too, that's the real overlap. The 40-150/4 is pretty unique and the absolute lightest FF 70-300s will still be heavier and larger than it (and external zooms).

There's a lot of insecure and uniformed users on both sides of the spectrum tbh. Richard himself brought up equivalence so I don't see any comment about it as unwarranted.

M4/3 users *should* be proud of the fact that the format has lenses for which there's no direct equivalent or anything in the same size class elsewhere (eg 40-150/4, 75/1.8, 35-100 - either one, PL40-500 f2.8-4, cheap xx-300s), that means just means the format has some pretty unique propositions.

Heck it's why I still shoot M4/3 alongside FF...

Everybody shooting any format and or lens don't always know what they have. Fact of the matter is this, FF users have been known to love them some MFTs cameras, so I find this talk of them somehow being insecure as pure nonsense.

Better to talk up the benefits of legendary MFTs IBIS as opposed to fighting
factual equivalence. The GH6 IBIS is exceptional, expect the same for the OM-1 along with great Len selections with stabilization. For Example.

Panasonic Lumix GH6 Image Stabilisation Test vs Sony A1 / Lumix GH5 II / Lumix S5

https://www.youtube.com/watch?v=0FSBBBugm3o

Richard Wong
23.2K subscribers

@Impulses... sorry I spotted my silly calculation and just changed my text now. Now your reply will not seem to make sense... sorry. I'll add another "sorry" 'cause I'm a Canadian.

"only valid for depth-of-field"—no, it isn't. A FF camera could do anything with an 80-300 f/8 lens that a MFT camera can do with a 40-150 f/4 lens. See https://www.dpreview.com/articles/2666934640/what-is-equivalence-and-why-should-i-care

An F4 MFT lens lets in a similar amount of light as an F8 FF lens, which is why they are 'equivalent' in much more than just DoF.

I agree entirely. What I don't understand, is why so many want to convert focal lengths and apertures of M43 lenses to the FF equivalent. I own a 300mm f4: I do not own a 600mm f8.

@Jerrin You are absolutely right. The problem is that the marketing pretends it's an ultra-compact 600 mm f/4, which it certainly is not.

Exactly, Jerrin.

I doubt most Olympus owners have a full frame camera, so a comparison is rather pointless. I want to know what the picture looks like with my camera and lens, not another brand.

You may think equivalence doesn't matter, but the reality is that it actually does. And no it doesn't only involve the field of view or depth of view. There is much more to equivalence than those basics.

What is however is that if you use a certain format, you most likely don't use another camera system and in that regard you are right, equivalence then is not a thing.

It's equal to a 35mm 80-300 f/8, note I dont use the term FF as all formats are actually full in themself, in two respects: Total light gathering and DOF. But of course you have to up the ISO in the 35MM camera two steps for it to be true... ( e.g ISO 800 to ISO3200)

@Impulses and @Alex Hanin,
Incorrect. When you use the same shutter speed and ISO, at F4 you have the same exposure value regardless of the sensor size. The difference lies in compression and depth-of-field. Not in amount of light transmitted.

@Jacob H: Is this myth still alive?

Do Full Frame users ever post on a Canon, Sony, Nikon thread and say their 400mm lens is equivalent to 200mm on a M4/3 camera? Of course not, so why mention it here?

" I doubt most Olympus owners have a full frame camera, so a comparison is rather pointless. I want to know what the picture looks like with my camera and lens, not another brand. " -Quiverbow

Guess I'm one of those exceptions since I own Pana, Oly, and Sony FF bodies and I find equivalence pretty useful, more so when cross shopping than when shooting but still.

" Do Full Frame users ever post on a Canon, Sony, Nikon thread and say their 400mm lens is equivalent to 200mm on a M4/3 camera? Of course not, so why mention it here? " -Quiver

It's come up, specially amongst those of us that shoot multiple formats, there's probably some FF user tired of hearing about how there's nothing equivalent to (or remotely the size of) my Oly 75/1.8 on FF mounts. This *doesn't* have to be antagonistic tbh.

@Jerrin, it's a lot to do with Olympus' marketing actually, that's probably the root of the problem, others might have done it too. They have marketed it that way with a subtle implication that people are getting the exact same thing just smaller, which of course would be amazing.

Of course with 35mm, you can shoot f/4 indoors with decent shutter speeds, and the noise is fine. If you go down to f4 indoors on m4/3, unless it's not a person that might move, it's a difficult aperture.

" @Impulses and @Alex Hanin, Incorrect. When you use the same shutter speed and ISO, at F4 you have the same exposure value regardless of the sensor size. The difference lies in compression and depth-of-field. Not in amount of light transmitted. " -Jacob H

You might wanna re-read what I wrote, haven't edited it since:

" For total light gathered it's like shooting at f8 (and the same SS w/higher ISO) on FF, that's all. "

I actually shoot both formats FWIW, and I wouldn't use F4 for the same purposes on both formats. I'm not sure why you think compression is relevant here as that's more closely tied to subject distance. These might be helpful:

https://m.dpreview.com/articles/2666934640/what-is-equivalence-and-why-should-i-care

https://m.dpreview.com/learn/2799100497/equivalence-in-a-nutshell

@Jacob H, if you start equivalencing one thing (focal length), then you've committed yourself to doing it for everything, can't pick and choose, b/c equations don't function that way. You multiply one side of an equation then multiply others side. 1" would be the way to go if we just get the same thing, but interestingly we don't make this argument with 1" sensors as it relates to 4/3 sensor, but then with 4/3 to full frame, suddenly things change?

Your exposure metering will be the same, but not the picture you get. If you keep the f/stop, aperture AND ISO the same on two different size sensors, it is a different exposure. I have a 1" (Sony RX100-II) and m4/3 (Using my E-M10-II for this comp), with the exact same settings (f/1.8, 1/15, ISO-200) they don't produce the same picture, my m4/3 gives a brighter cleaner picture.

I have to either increase the shutter speed or close f/stop on my m4/3 to get the same picture as what my Sony gives me.

The thing though is that no FF camera manufacturer or third party FF lens manufacture is making f/5.6 or f/8 zooms (or high quality f/8 primes in the 300-600 range), or 150mm f/3.5 primes for example. So if it is a FOV you want at a certain size, and no one else is making it, then it doesn't matter if it isn't equivalent in total light gathering to something else you don't want to get anyways.

It is good to know when deciding on equipment exactly what level of performance you are getting and not to think it can do everything that the lens with twice the iris can do.

@OSPhoto,
I never argued that the images would be the same. Obviously there’s a difference in image quality due to sensor size, MPs and pixel pitch (a/o). The remark of the author was that there’s no equivalent lens in FF to compare the size, weight and range with this 40-150/F4. My statement is that in terms of size, weight and range you can certainly compare this M43 lens with a 80-300/F4 FF lens. The F4 of both lenses produce roughly the same exposure value and view angle, but obviously the M43 lens has a larger DOF and different compression. You don’t have to look for an 80-300/F8 to be able to compare size, weight and range.

@Jacob H: "I never argued that the images would be the same"—but that would be the definition of 'equivalent'. If they aren't, or at least not as similar as they can sensibly get, then it's not equivalence. Equivalence describes the choice and settings of camera/lens combinations of different formats that set the best preconditions for images to become as similar as possible.

Jacob: why do you care more about exposure than about the results you get? What does “f/4” bring you in itself?

Also, compression will be the same.

@Jacob H, those lenses don't produce the same FOV though. It's the sensor behind the 40-150 f/4 that allows it to give you the same FOV because it crops the view, but that also means it crops the total amount of light it is gathering.

The lenses themselves don't actually have the same FOV, this can trip people up. They only have the "same" "equivalent" FOV, but if we equate their FOV, then we have automatically also equated all the other factors related to the performance. Let's just take their limit. 150 f/4 and 300 f/4.

f-stop = focal length / iris diameter. So 150 f/4 w/ an iris diameter of 37.5 is in no way going to capture as much total light for the 300mm FOV as 300 f/4 with an iris diameter of 75.

They do produce the same FOV with their respective sensors, yes, but while the exposure metering (light intensity) is the same, the total light is different, and therefore the result of your final exposure/pic is different, so I can't really call that the "same" exposure.

@Jacob H, is author wrong though? Unless there's a 70-300 or 70-200 f/4 FF lens that weighs within 20% of the 382g that this lens weighs, you're not going to find this package elsewhere.

Olympus 40-150 f/4: 382g
Canon 70-200 f/4: 695g
Panasonic 70-300 f/4.5-5.6: 790g
Panasonic 70-200 f/4: 985g

None of those are comparable in weight. Of course all of those are actually longer focal lengths, with larger iris', and capture more total light, but that's not the question, and that's the give and take.

I suppose if FF manufactures wanted to cannibalize the m/43 market, they could make slower equivalent zooms that will give you the same end result picture. Of course there's also the argument that since you lose the FF advantage if you do that , why should I buy a FF body which is generally more expensive and has fewer features, only to get lenses that give me the eq. total light to m4/3? If I buy the FF body with the features of my m4/3 camera, it would be far more expensive.

^ There's lighter / slower FF tele zooms in the ~550g range but they're still a good 40% heavier than the Oly, and larger, but I do think there's a market for that kinda thing.

Not everyone wants to shoot multiple systems, customer 1 may want (or is already invested in) FF for XYZ (say, a 35/1.4) and would be fine with a slower tele, while customer 2 may want (or is already invested in) M4/3 for ABC (say a pancake zoom, w/e) but may share the same tele needs as customer 1.

It's good for both/all systems and formats to have an ability to scale up or down and not be focused on a more narrow performance envelope. I think some overlap is a good thing.

Anyway... The lightest E mount teles I'm aware of:

Tamron 70-300 f4.5-6.3 - 148mm long & 545g
Tamron 28-200 f2.8-5.6 - 117mm long & 575g

And the lightest one for RF that I think overlaps the most with smaller format stuff:

Canon 100-400 f5.6-8 - 165mm long & 635g

I think on a high MP body that one is closer to some of the M4/3 xx-300 stuff, or comparable to the PL50-200 but built to totally different standards (no sealing, TCs, etc), course a high MP body will run you 6x the price of that lens heh. The smaller M4/3 stuff like the 35-100/2.8, 40-150/4, etc. are more unique propositions on the basis of size alone. Then there's really tiny stuff like the 35-100 f4-5.6...

I see plenty of value in both formats and plenty of areas where I'd actually like more overlap tbh.

The FZ1000 is even lighter, why buy this heavy m43 gear?