M43 flexibility for Macro photography with Oly 60mm F2.8, extension tubes, raynox M-250 and MC-20 TC

junmoe62 wrote:

Hi John,

Thanks for your post and bringing a more accurate and scientific approach to my claims.

You’re absolutely right on (Almost) everything you said (Your assumptions about the actual “real magnification’” of the setup were not correct), so I’m glad you could correct the errors.
It seems I got it all reversed! When I was talking about FF Eq. magnification I should have used the word “crop” and about the TC I should have used the term “magnification” instead of “crop”... my bad...

As I’ve previously stated and as you can see, I’m not much of a tech guy.

After, to be fair, English is not my mother tongue. What I actually meant was that, for example, the framing for 1x magnification lens on M43 is similar to the framing of a 2x magnification lens on a FF. Meaning that the composition of the picture would be the same. I never meant that the IQ and DOF of the picture would actually be the same between and 1x M43 setup and a 2x FF setup. I thought that it was obvious to most.

I know what you meant, but the way you said it was wrong.

So indeed it was a shortcut that could be confusing, I agree. But then, I guess many here on the forum come from all around the world and don’t necessarily have the perfect vocabulary (like myself), probably don’t have a PhD in science and optics (me included), are there to relax and don’t always want to keep everything so serious and scientifically accurate in all the phrasing (I’m guilty too).

No PHD necessary. Words, and their definitions, are pretty easy to understand.

When you think about it, even on a daily basis we always use shortcuts in our languages that don’t always represent things in a scientific accurate way.

Not getting basic terminology right can lead to a lot of confusion. Again, it's not science and no PHD required.

Regarding the diopter, I know that the theory says that you do not use light, but in practice, I always find myself having to adjust the power of the flashes up when I put it on.

Because the magnification changed and the field of view dropped, so there is less surface area reflecting light back into the camera and the flash had to fire longer to compensate. So there's no light loss due to the diopter, but the increase in mag will require more light to get a proper exposure. Happens with extension tubes (to a slightly greater extent), teleconverters, etc. Any time the mag goes up the exposure will have to change to compensate.

That’s probably due to something else, like inverse square law or the position of the light source relative to the subject and front of the lens, I don’t know, but the fact is that it somehow does have an impact.

You're on the right track.

And finally about the maximum magnification of my setup which consists of 2x 10mm extension tubes + 16mm extension tubes + MC20 TC + Raynox M-250, I made the test you requested since I don’t want you to think I’m here to spread misinformation It fills the width of the frame with about 3mm. So 17.3 / 3 = 5.76 magnification. So when I said that the setup gave 8x FF Eq. magnification (by which I meant same framing than 8x mag on FF), I was actually understating the numbers. Let’s round out to 5.5x which gives the same framing than 11x on FF. But let’s make it 10x for safety purposes...

No, lets make it 5.76x cause that's the magnification at the sensor. Cropping the image circle, like cropping a photo in post, does not change the magnification. You're still trying to claim that cropping increases the magnification.Cropping just creates an enlargement, so the subject looks larger on screen or in print. But it won't reveal more detail like increasing the magnification can and that's just one reason why they two are not the same.

When I'm shooting with a macro lens set to 1x mag on my APS-C sensor (1.6x crop) I'm shooting at 1x mag. I'm not shooting at 1.6x.

If I add a 1.4x teleconverter between the lens and camera I'm now shooting at 1.4x due to the magnification factor of a the teleconverter. I'm not shooting at 2.4x (1.4 x 1.6).

In both cases the crop factor of my sensor makes no difference in the magnification. Will the subject look larger in a print or on a screen than the same image taken with a full frame sensor at the same magnification? Sure, but that's the nature of creating an enlargement.

BobT3218 wrote:

John K wrote:

junmoe62 wrote:

The gear I’m using for true macro is primarily the EM1 X (sometimes the EM1 II) with Olympus 60mm F2.8 macro, this gives up to 2x magnification in FF equivalence.

No. Cropping an image, in post or with a smaller than full frame sensor, creates an enlargement but does not change the magnification of the subject that was projected onto the sensor. You're still shooting at 1x. FWIW: I shoot with an APS-C sensor.

You are technical correct but overly pedantic I think. It's true that a life sized image on the sensor, in photographic jargon, is called 1:1 magnification regardless of the sensor size.
The OP qualified his "2x magnification" comment with "FF equivalence". This is a m4/3 forum. We all know what he means.

The problem is using the word "magnification". When the mag changes diffraction effects get worse, depth of field drops, etc. None of that happens when you crop a photo. "Full frame equivalent framing" would be a more accurate term. Maybe I am being pedantic, but I've had to field way too many questions from confused beginners due to how everyone is shuffling terminology.

junmoe62 wrote:

So, let me ask you a question. I definitely don’t want to get into all the equivalence controversy thing, because I have not much interest in all that stuff, and I most of the time have better things to do, but I’m interested in your view on that. My question is : Do you think it is totally unacceptable to say, for example, a 300mm F4 on a m43 body is roughly equivalent to a 600mm F8 on FF body?

It's the same, but only in the sense that the field of view will be the same. But if the focal length actually changed then there would also be a change in perspective. As you go from a wider angle to a narrower one objects in the scene start to appear closer together. That perspective change doesn't happen when you crop a photo, no matter how or when the crop is done.

If you think it is unacceptable, then fine!

Not unacceptable, but not the same. Sorry.

But if you think it is acceptable to some extent (like the vast majority on the internet), I could argue that following your thought process, from the same distance, which would translate to same framing, if you fill the frame with a ruler of 1 meter, the m43 system would give you a magnification of 17.3mm / 1000mm = 0.0173, while the FF system would give you 36mm / 1000mm = 0.036.

But you can't fill the frame with a ruler on both systems -the m43 is smaller. If you're saying that you are filling the frame on both then either the m43 is at a lower magnification (there's that word again ) or there's a difference in distance between the subject and the sensor with the ruler being closer to the full frame sensor. In either case the magnification isn't the same, if it were you'd only see half of the ruler in the m43 photo because the image is being cropped. At the same mag and Fstop depth of field will be the same for both sensors. But if you shoot at 1x with the full frame sensor, and shoot at .5x with the m43 but call it 1x due to the crop factor then the m43 image will have more depth because the mag is lower. That's the main reason why I think that cropping shouldn't be viewed as magnification, and why the two really are not the same.

Does that make the whole theory totally useless and cannot be used to have a rough idea of what to expect? I personally don’t think so, YMMV.

Yes it does invalidate it because of the differences in depth of field, diffraction softening, and I'm probably forgetting a few others. The problem is that you're assuming someone just getting into macro is going to know everything that you do, not realizing that juggling terminology could be confusing.

I wish you a nice day and happy shooting!

Regards,

Julien

Same

FWIW: If the image quality on an m43 camera ever gets to the level of an APS-C sensor I'd make the jump in a heartbeat just to take advantage of that 2x crop.

pannumon wrote:

John K wrote:

Agreed, except for the magnification.

Yes, yes, the definition of magnification is very clear.

One of the benefits of shooting with a smaller than full frame sensor is that the subject will look larger in the final image because the scene is cropped, and that allows you to fill the frame at lower magnifications than shooting full frame. Lower mag = more depth of field. It's the reason why I'm shooting with an APS-C camera (Canon 80D) instead of shooting full frame.

Since the discussion is now about semantics,

Sorry, but the conversation is about using correct terminology so that new people getting into macro don't get confused.

when using a native Micro Four Thirds (µ4/3) lens on a camera with 4/3 sensor, there is no more cropping than there is when using a FF lens on FF sensor. The same applies for compact cameras and smart phones. Nobody says that a smartphone has a crop sensor or that the image is cropped on a smartphone.

OK, but no one has been talking about using m43 lenses. Not sure where you're going with that one.

However, there is crop when you are using a FF lens on APS-C camera. There is also crop when I am using my Canon FD lenses on my µ4/3 cameras. There is less crop when I am using a focal reducer.

No arguments there.

You can also get the exact same effect by shooting full frame and cropping in post. If the price ever drops I'd consider buying a 5dsr and crop its 50MP full frame images down to a 1.6x crop (roughly an 18MP image I think).

But you cannot use the same µ4/3 lens on FF, because the image circle does not cover the FF sensor.

...and no one has mentioned that, and it's kinda irrelevant to the discussion.

For the same reason, the image is not cropped when used on 4/3 sensor camera. µ4/3 is an independent system, not a crop of FF standard.

...but it can use full frame lenses, and when you put a full frame lens on a m43 (or any other smaller than full frame camera) the image circle that's projected by the lens gets cropped. It does not get magnified. That's what we've all been discussing.

As you say, in FF/APS-C world, APS-C are often used instead of FF because of the higher pixel density.

Nope, I said used one for the crop factor cause I can make the subject look larger in the frame at a lower magnification than I can on a full frame camera. Lower mag = more depth of field, and it's a big advantage especially when shooting single frames with a lens that's stopped down.

Very high megapixel FF sensors would make APS-C techically inferior, because the same result could always be obtained by cropping. However, this does not apply for µ4/3.

Actually it kinda does, and for the same reasons. The 5ds /  5dsr would make APS-C nearly obsolete if those cameras were the same price. If the pixel counts get any higher the same thing could happen to m43 as well. Or if the image quality of m43 gets to be as good as APS-C then APS-C could become obsolete in some situations.

In summary, smaller sensor size does not infer cropping.

It does when the lenses are full frame versions

Getting tougher and tougher to have a decent conversation in the echo chambers that people want to be in...

John K wrote:

junmoe62 wrote:

Regarding the diopter, I know that the theory says that you do not use light, but in practice, I always find myself having to adjust the power of the flashes up when I put it on.

Because the magnification changed and the field of view dropped, so there is less surface area reflecting light back into the camera and the flash had to fire longer to compensate. So there's no light loss due to the diopter, but the increase in mag will require more light to get a proper exposure. Happens with extension tubes (to a slightly greater extent), teleconverters, etc. Any time the mag goes up the exposure will have to change to compensate.

I'm wondering how just how large an effect you would expect this magnification-caused change in illumination requirement to be with a close-up lens. You say it happens to a slightly greater extent with extension tubes, teleconverters etc, so presumably that means that if you use a close-up lens and increase the magnification you would need to add almost as much light as if you had made the same change in magnification using extension tubes, teleconverters etc. Have I understood you correctly?

And presumably the etc includes macro lenses, for example the MPE-65?

gardenersassistant wrote:

John K wrote:

junmoe62 wrote:

Regarding the diopter, I know that the theory says that you do not use light, but in practice, I always find myself having to adjust the power of the flashes up when I put it on.

Because the magnification changed and the field of view dropped, so there is less surface area reflecting light back into the camera and the flash had to fire longer to compensate. So there's no light loss due to the diopter, but the increase in mag will require more light to get a proper exposure. Happens with extension tubes (to a slightly greater extent), teleconverters, etc. Any time the mag goes up the exposure will have to change to compensate.

I'm wondering how just how large an effect you would expect this magnification-caused change in illumination requirement to be with a close-up lens. You say it happens to a slightly greater extent with extension tubes, teleconverters etc, so presumably that means that if you use a close-up lens and increase the magnification you would need to add almost as much light as if you had made the same change in magnification using extension tubes, teleconverters etc. Have I understood you correctly?

Extension tubes (and a teleconverter as well) move the lens further away from the image plane and as the image circle expands the intensity of the light drops. You don't get that same effect with a diopter. No matter how you increase the magnification there is going to be less surface area reflecting light back into the lens as the mag goes up, and it was the original reason for effective Fstops. Back in the stone age, when we used hand held light meters, you had to compensate for that drop in light by adding stops to the aperture value displayed in the meter (the meter assumes that you're shooting at infinity). Effective Fstops has since been hijacked to use in diffraction calculations but I think it's just a convenient way of dealing with the aperture getting further from the sensor as the mag goes up (as the distance between the aperture and sensor increases light has more room to diffract).

And presumably the etc includes macro lenses, for example the MPE-65?

It does, but one way to compensate for it is to get the light source closer to the subject. If you're using a macro twin flash that drop in reflected light off of the scene as the mag increases can be offset due the distance between the flash heads and the subject getting shorter. It's possible to increase the mag and yet keep the flash power the same and still get a good exposure simply because the flash, mounted to the end of the lens, is closer to the subject.

junmoe62 wrote:

John K wrote:

junmoe62 wrote:

So, let me ask you a question. I definitely don’t want to get into all the equivalence controversy thing, because I have not much interest in all that stuff, and I most of the time have better things to do, but I’m interested in your view on that. My question is : Do you think it is totally unacceptable to say, for example, a 300mm F4 on a m43 body is roughly equivalent to a 600mm F8 on FF body?

It's the same, but only in the sense that the field of view will be the same. But if the focal length actually changed then there would also be a change in perspective. As you go from a wider angle to a narrower one objects in the scene start to appear closer together. That perspective change doesn't happen when you crop a photo, no matter how or when the crop is done.

Well John, I’m afraid to tell you that this time you are the one guilty of spreading misinformation!

If anything I'm guilty of over simplifying it, but you took care of that below:

The focal length of a lens alone has absolutely no effect on the perspective! Your position relative to the subject does. You can experiment yourself by taking a picture of a subject from the same position with a zoom lens on your camera. Take a picture at the widest angle you can, then zoom to the max and repeat. You will see that the perspective of the zoomed picture will match the one from the same location on your wide angle shot (minus the potential optical flaws like lens distortions (pinch, barrel and so on) obviously).

So when you zoom with your lens, you basically “cropping” the framing... and I’m not counting DOF and other aspects.

Which means, if you take a picture of the same subject, from the same location with a 300mm on m43 and a 600mm on FF, you should have the exact same framing and perspective. You just cropped, and crop doesn’t affect perspective...

I just googled the first article talking about that to link for you as a reference, in case my words are not enough to convince you :

https://martinbaileyphotography.com/2017/04/10/the-effect-of-subject-distance-and-focal-length-on-perspective-podcast-568/

That pretty much sums up why 800mm on m43 isn't the same as 800mm on a full frame camera. Let me try this from another angle:

If I shot with a full frame sensor using a 300mm lens, cropped the resulting images in post to a 2x crop factor, and claimed that the resulting photos were shot with a "600mm virtual lens" you'd call me nuts. Cropping in post doesn't change the focal length that the image was taken with. But since cropping in post, and cropping a full frame image circle with a smaller than full frame lens, is functionally the same then the focal length doesn't change no matter what camera body you use. When you crop an image, no matter how you do it, the only thing that changes is the field of view and how large the subject looks in the frame. This is great time to use terms like "full frame equivalent field of view".

I remember these discussions in the APS-C community, and they were really painful. Way too many people wanted to think that the 1.6x crop was somehow magical, like the rules of photography and physics had to be rewritten to be re-written to explain the magic that was nothing more than a simple crop.  Seems the m43 community isn't there yet, and I regret stepping in it...

If you think it is unacceptable, then fine!

Not unacceptable, but not the same. Sorry.

But if you think it is acceptable to some extent (like the vast majority on the internet), I could argue that following your thought process, from the same distance, which would translate to same framing, if you fill the frame with a ruler of 1 meter, the m43 system would give you a magnification of 17.3mm / 1000mm = 0.0173, while the FF system would give you 36mm / 1000mm = 0.036.

But you can't fill the frame with a ruler on both systems -the m43 is smaller. If you're saying that you are filling the frame on both then either the m43 is at a lower magnification (there's that word again ) or there's a difference in distance between the subject and the sensor with the ruler being closer to the full frame sensor. In either case the magnification isn't the same, if it were you'd only see half of the ruler in the m43 photo because the image is being cropped. At the same mag and Fstop depth of field will be the same for both sensors. But if you shoot at 1x with the full frame sensor, and shoot at .5x with the m43 but call it 1x due to the crop factor then the m43 image will have more depth because the mag is lower. That's the main reason why I think that cropping shouldn't be viewed as magnification, and why the two really are not the same.

In my example I was still talking about the 300mmF4 m43 lens VS the 600mmF8 FF lens. I though once again that it was obvious... sin

ce I precisely said “from the same distance, which would translate to same framing”.

My mistake.

Why wouldn’t I be able with those setups, from the same position and the ruler at the same distance, be able to fill the width of frame with the exact same 1 meter mark? Yet I believe the m43 would give a 0.0173x mag. while the FF would give 0.036x mag.

Is the 300mm m34 lens projecting a smaller image circle? Is so then it's focal length is probably a m43 equivalent (like the EF-S lenses for Canon APS-C camera bodies).

So, since we saw above that FL has nothing to do with perspective if you shoot a subject from the same distance, and that the DOF from a F4 on m43 is very similar to a F8 on FF (btw, I’m still referring to the same lenses mentioned above, in case it wasn’t clear enough), don’t you think that feels very close, in the concept, to crop in post or with the sensor? Maybe the semantics are not of absolute perfection and accuracy, but honestly, that’s a good enough approximation for me.

Does that make the whole theory totally useless and cannot be used to have a rough idea of what to expect? I personally don’t think so, YMMV.

Yes it does invalidate it because of the differences in depth of field, diffraction softening, and I'm probably forgetting a few others. The problem is that you're assuming someone just getting into macro is going to know everything that you do, not realizing that juggling terminology could be confusing.

Well, honestly I don’t think this kind of tight and minute subtleties in the photography jargon is gonna appeal to, nor affect the photos of macro beginner!

I'd be pretty bummed if I got into m43 thinking that the 2x crop would actually give me more mag, and with it more detail, only to find out that it's just a crop.

Look I'm not trying to bash you, the camera you use, or anything else. Putting anyone, or anything, down doesn't do me any good. I was just trying to clear up some important terminology. If you wanna believe that you're actually getting more magnification, more focal length, or even a better parking spot just because you're using a 2x crop factor sensor that's fine. I'll leave you to your echo chamber that seems to be the m43 community.

pannumon wrote:

This is basic equivalence, you shoot f/8, 1/500s, ISO 400 on µ4/3 camera, or you can shoot f/16, 1/500s, ISO 1600 on FF camera. The same depth of field, same shutter speed, same amount of quantum (light) noise. There is no benefit from using the smaller sensor (except lower relative read noise and slightly better IQ), but on the other hand there is no benefit of using the larger sensor either.

It all comes to pixel density (more megapixels on the subject).

You touched on something that has seriously puzzled me, and I'm not trying to argue with you I'm actually interested in learning something.

A lot of people treat digital sensors like they are solar cells, and calculate exposure based on surface area. But a digital sensor is not a single piece of light sensitive silicon like a solar cell, it's made up of millions of light gathering pixels. So why would the exposure change between shooting full frame and a crop factor sensor when the intensity of the light falling on the individual pixels is the same?

If I had the money I would buy two 5ds cameras and using gaffers tape I'd tape off one of the sensors to make it a 1.6x crop camera and see if the exposure between it and the full frame version is different when shooting a 33% grey card.