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

junmoe62 wrote:

gardenersassistant wrote:

John K wrote:

gardenersassistant wrote:

John K wrote:

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.

Thanks John, but my question was about close-up lenses (what you refer to as "diopters"). It was this: "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?"

Key word is "almost". A teleconverter and extension tubes move the lens further away from the image plane, and as the light expands the intensity will drop. You don't get that effect with a closeup lens.

And my other question was whether the same would apply if you used a macro lens such as the MPE-65 rather than extension tubes or a teleconverter for that side of the comparison.

If you're gonna set up some sort of side by side comparison and attempt to slice my throat go ahead. Just keep in mind that there will be differences in the physical size of the aperture, and potential differences in the distance between it and the image plane. I can only tell you that as the mag goes up, no matter how, the intensity of the light will drop due to the decrease in surface area reflecting light back into the lens.

That is the core issue for me - you say that increased magnification reduces the light intensity reaching the sensor, however that magnification is achieved. However, this seems inconsistent with my experience with close-up lenses; when I change the magnification I don't have to change the flash power (I use a manual flash, so I think I would notice it if anything other than a small difference was going on).

Puzzled about this, I did an experiment, using as an example the difference in light intensity as between a magnification of 1:1 and 4:1, first with an MPE-65. I used it on a Panasonic G9. in aperture priority mode, using available light, I shot it at 1:1 and 4:1 with the same f-number and ISO for both shots.

Based on the effective f-numbers for these magnifications, I calculated an expected difference of light intensity of around 2.5 stops. The illustration below shows this was about right. The camera chose 1/50 sec for the 1:1 shot and 1/10 sec for the 4:1 shot. This is a difference of 2 and 1/3 stops, and the 4:1 shot is slightly darker. So this result is consistent with a difference in light intensity of around 2.5 stops.

Click on Original size beneath the image to see the animation.

With the same camera and subject, I then captured two images using a Raynox MSN-202 close-up lens on a 45-175 lens, one using 45mm and one using 175mm. This gave magnifications very similar to the ones with the MPE-65, 1.15:1 and 4:1. Here too I used aperture priority mode, using available light, with the same f-number and ISO for both shots.

The following illustration shows that the camera chose the same shutter speed for both shots, and the lightness of the two images was very similar. This means that the light intensity was pretty much the same at the two magnifications.

Click on Original size beneath the image to see the animation.

This seems to me to confirm my impression from shooting flash - if changing magnification when using close-up lenses does alter the light intensity reaching the sensor, then it doesn't change it by much.

There is a bit of a twist to this. I did similar comparisons with other close-up lenses (Raynox 150 and 250, Canon 500D, Marumi 200 and two Marumi 330s, one reversed on the other), shooting pairs of shots at 45mm and 175mm as I had for the Raynox 202.

These pairs all gave the same result, which was that the camera chose the same shutter speed for both shots in the pair, and the lightness of the shots in each pair was almost the same, but they differed very slightly, and differed in the same way for every pair. Here is the Raynox 202 comparison again, but this time with the histograms aligned.

Click on Original size beneath the image to see the animation.

We can see that the 4:1 shot was very slightly darker than the 1.15:1 shot.It is a very small difference. For example, thinking back to the MPE-65 example, the illustration below shows what a 2 and 1/3 stop difference looks like on those histograms.

Click on Original size beneath the image to see the animation.

The difference we are seeing with the close-up lenses is tiny compared to that. (Presumably it is less than 1/3 stop otherwise the camera would have changed the shutter speed to keep to the required exposure compensation.)

I wondered if this might have something to do with the design of the 45-175, which does not extend as you increase focal length. However I get the same effect with a 45-200, which does extend.

Curious. I wonder what is causing this.

Hi Nick,

That’s a very interesting experiment that you did there! Thanks for taking the time to do it.

You are welcome. I find experiments help me understand what is going on. And when I think I already know what is going on, they serve to support (or contradict) my understanding of the situation.

Am I right in assuming that your working distance didn’t change during your test? By that I mean that your position relative to the subject didn’t change?

For the MPE-65 the working distance changed between 1:1 and 4:1. For the close-up lens the working distance did not change between those two magnifications. This is because the close-up lens was mounted on a camera lens that does not physically extend/contract as the focal length changes, and it is by changing the focal length that one changes the magnification.

If it is the case (At least regarding dioptres / magnifying glass), it would mean that increasing the magnification alone (without getting closer to the subject) doesn’t change exposure in a meaningful way.

That is what the test indicated (taking into account the camera lens characteristic mentioned in this post which has nothing to do with macro/closeup/magnification).

This result actually doesn’t look so surprising when you think about it. When you take a picture of a magnifying glass while still showing the surroundings, the area inside the magnifying glass doesn’t look darker (in a meaningful way).

Just for the sake of illustrating what I’m saying, here is a picture that was on the Wikipedia page for the definition of “magnification” :

Obviously, this picture doesn’t remotely represent any sort of scientific evidence.

Maybe not, but interesting, creative and highly suggestive all the same.

One could probably argue that if the light source is positioned behind the magnifying glass, the latter could concentrate the light on te magnified area, I guess. But your experiment seemed quite accurate and couldn’t suffer from that “problem”.

Now though, I’m wondering if you would still get the same result when changing you working distance. Because that’s what’s happening when you add a diopter on a lens. So while using the bare lens at it’s closest focusing distance, do you still get the same exposure than when using that same lens + the diopter At the closest focusing distance?

Yes.

I photographed a sheet of printer paper in natural light, using aperture priority with zero exposure compensation, using the same f-number and ISO for each shot. The camera used the same shutter speed in each case.

G80 with 45-175 at 175, working distance around 900mm.

G80 with 45-175 at 175 with Raynox 250, working distance around 110mm.

G80 with 45-175 at 175 with Raynox 202, working distance around 35mm.

If the exposure gets darker in the latter configuration, I guess my guts feeling that the inverse square law was partly responsible is probably closer to the truth than I originally thought!

When you think about it, your white sheet of paper is lit with roughly the same light intensity across. And if you don’t change the working distance, it behaves a little bit like “cropping”. You could also see that as the difference between different sensor sizes. You would have the same exposure on a FF sensor area and a m43 sensor area. The total light gathered wouldn’t be the same, but since the light intensity by area is the same, the exposure is the same. My analogy is probably horrible, but I think it’s a little bit the same logic in the end!

Have a nice day!

Cheers,

Julien

gardenersassistant wrote:

John K wrote:

pannumon wrote:

gardenersassistant wrote:

pannumon wrote:

John K wrote:

No need, because depth of field can be calculated but it's also perception based. Take a look at the Canon MP-E 65mm manual , specifically the depth of field chart. No where does it mention anything about reproduction ratios and that's because it doesn't matter how large you view the print. The depth is fixed at the time of exposure. Any change in depth after that is perceived and not actual.

In order to calculate depth of field, the acceptable size of circle of confusion needs to be determined. This depends heavily on final size and viewing distance of the photo. This is a factual statement, not a matter of an opinion.

For example, see https://en.m.wikipedia.org/wiki/Depth_of_field

Canon may simplify things in their manual, but that does not change the facts. You may define "depth" as you like, but depth of field is already defined, although you may not like the definition.

As I said, I have have a hard time with this, but now I see.

Doesn't this extended argument come down essentially to John believing that what matters is the magnification on to the sensor, and you believing that what matters is an image as viewed, which depends on enlargement in addition to the magnification?

Seems to me that both ways of looking at it have their uses, depending on the context, rather than one or other of them being the ... uniquely correct/valid/useful/appropriate way of looking at it.

Actually the question was whether smaller sensors provide benefits for macro photography over larger ones.

The answer to that question is "Yes". Easier to fill the frame with the subject at lower magnifications, and being able to shoot at a lower mag results in more depth of field at the same apertures.

I think that needs some qualification. Taken at face value that would mean that 1/2.3" is better than APS-C. I'm sure that isn't what you had in mind.

And looking at it from the FF side of things, what is the practical benefit of getting more depth of field at the same aperture? Why require the use of the same aperture? For example, you typically shoot at f/11 using an MPE-65 on a 1.6X crop factor camera. A full frame shooter could get the same depth of field as you do by using a smaller [EDIT - larger!] f-number. As it happens if they too used an MPE-65 they couldn't reduce the aperture quite enough to match your f/11 for DOF, but if they used an f/22 or f/32 macro lens they could. Here too, I think some qualification is needed.

All true Nick -but they'd have to change the aperture and eat the diffraction penalty. Always trade offs.

A m43 sensor is a good choice if all you carte about is getting the subject as large as possible in the frame. Is it the best choice for image quality? No...

John K wrote:

gardenersassistant wrote:

John K wrote:

pannumon wrote:

gardenersassistant wrote:

Doesn't this extended argument come down essentially to John believing that what matters is the magnification on to the sensor, and you believing that what matters is an image as viewed, which depends on enlargement in addition to the magnification?

Seems to me that both ways of looking at it have their uses, depending on the context, rather than one or other of them being the ... uniquely correct/valid/useful/appropriate way of looking at it.

Actually the question was whether smaller sensors provide benefits for macro photography over larger ones.

The answer to that question is "Yes". Easier to fill the frame with the subject at lower magnifications, and being able to shoot at a lower mag results in more depth of field at the same apertures.

I think that needs some qualification. Taken at face value that would mean that 1/2.3" is better than APS-C. I'm sure that isn't what you had in mind.

And looking at it from the FF side of things, what is the practical benefit of getting more depth of field at the same aperture? Why require the use of the same aperture? For example, you typically shoot at f/11 using an MPE-65 on a 1.6X crop factor camera. A full frame shooter could get the same depth of field as you do by using a smaller [EDIT - larger!] f-number. As it happens if they too used an MPE-65 they couldn't reduce the aperture quite enough to match your f/11 for DOF, but if they used an f/22 or f/32 macro lens they could. Here too, I think some qualification is needed.

All true Nick -but they'd have to change the aperture and eat the diffraction penalty. Always trade offs.

Always trade offs for sure. In this case they would have changed the aperture so as to get the same DOF as you, so with the same field of view as you their trade off for getting the same DOF as you would be to increase their diffraction penalty to be the same as the diffraction penalty you have to eat.

If that were not the case, and FF did have an extra diffraction penalty compared to APS-C for a given field of view and DOF then you, using APS-C, would surely have an extra diffraction penalty compared to mFT, and even more so compared to 1/2.3". (I don't think that is the case of course, and I'd be surprised if you did, but I think that is where the logic of this particular APS-C vs FF argument leads.)

A m43 sensor is a good choice if all you carte about is getting the subject as large as possible in the frame. Is it the best choice for image quality? No...

And by the same token, wouldn't a full frame sensor be better than APS-C? And medium format better still? In which case, perhaps I should write "An APS-C sensor is a good choice if all you care about is getting the subject as large as possible in the frame. Is it the best choice for image quality? No...". Coming from a full frame user like me, I think that might be taken to be a bit condescending.

I think it is more complicated than simply "wanting to get the subject as large as possible in the frame", or that any particular sensor size is optimal for close-up/macro. As we both believe, there are always trade-offs.

gardenersassistant wrote:

John K wrote:

gardenersassistant wrote:

John K wrote:

pannumon wrote:

gardenersassistant wrote:

Doesn't this extended argument come down essentially to John believing that what matters is the magnification on to the sensor, and you believing that what matters is an image as viewed, which depends on enlargement in addition to the magnification?

Seems to me that both ways of looking at it have their uses, depending on the context, rather than one or other of them being the ... uniquely correct/valid/useful/appropriate way of looking at it.

Actually the question was whether smaller sensors provide benefits for macro photography over larger ones.

The answer to that question is "Yes". Easier to fill the frame with the subject at lower magnifications, and being able to shoot at a lower mag results in more depth of field at the same apertures.

I think that needs some qualification. Taken at face value that would mean that 1/2.3" is better than APS-C. I'm sure that isn't what you had in mind.

And looking at it from the FF side of things, what is the practical benefit of getting more depth of field at the same aperture? Why require the use of the same aperture? For example, you typically shoot at f/11 using an MPE-65 on a 1.6X crop factor camera. A full frame shooter could get the same depth of field as you do by using a smaller [EDIT - larger!] f-number. As it happens if they too used an MPE-65 they couldn't reduce the aperture quite enough to match your f/11 for DOF, but if they used an f/22 or f/32 macro lens they could. Here too, I think some qualification is needed.

All true Nick -but they'd have to change the aperture and eat the diffraction penalty. Always trade offs.

Always trade offs for sure. In this case they would have changed the aperture so as to get the same DOF as you, so with the same field of view as you their trade off for getting the same DOF as you would be to increase their diffraction penalty to be the same as the diffraction penalty you have to eat.

If that were not the case, and FF did have an extra diffraction penalty compared to APS-C for a given field of view and DOF then you, using APS-C, would surely have an extra diffraction penalty compared to mFT, and even more so compared to 1/2.3". (I don't think that is the case of course, and I'd be surprised if you did, but I think that is where the logic of this particular APS-C vs FF argument leads.)

All true.

A m43 sensor is a good choice if all you carte about is getting the subject as large as possible in the frame. Is it the best choice for image quality? No...

And by the same token, wouldn't a full frame sensor be better than APS-C? And medium format better still? In which case, perhaps I should write "An APS-C sensor is a good choice if all you care about is getting the subject as large as possible in the frame. Is it the best choice for image quality? No...". Coming from a full frame user like me, I think that might be taken to be a bit condescending.

With the 80D I'm only shooting with one less stop of dynamic range than the 5D Mk IV, a full frame 35MP sensor.Since I'm not using AF or any other feature of the camera dynamic range is pretty much the only thing I care about. Noise is so easy to deal with in post that it's practically a non issue.

Would the 5D 4 still have better IQ? Sure. But I know several photographers that have both cameras and they shoot macro with the 80D.

As for intent: I'm never condescending in my posts, at least I don't intend to be. If you could Facetime with me, or Zoom chat, I think you'd have a much better impression of me. All too easy to read into what someone writes.

I think it is more complicated than simply "wanting to get the subject as large as possible in the frame", or that any particular sensor size is optimal for close-up/macro. As we both believe, there are always trade-offs.

Absolutely true.  It all depends on what you're trying to accomplish and what you're willing to sacrifice to get it.

John K wrote:

gardenersassistant wrote:

John K wrote:

gardenersassistant wrote:

John K wrote:

pannumon wrote:

gardenersassistant wrote:

Doesn't this extended argument come down essentially to John believing that what matters is the magnification on to the sensor, and you believing that what matters is an image as viewed, which depends on enlargement in addition to the magnification?

Seems to me that both ways of looking at it have their uses, depending on the context, rather than one or other of them being the ... uniquely correct/valid/useful/appropriate way of looking at it.

Actually the question was whether smaller sensors provide benefits for macro photography over larger ones.

The answer to that question is "Yes". Easier to fill the frame with the subject at lower magnifications, and being able to shoot at a lower mag results in more depth of field at the same apertures.

I think that needs some qualification. Taken at face value that would mean that 1/2.3" is better than APS-C. I'm sure that isn't what you had in mind.

And looking at it from the FF side of things, what is the practical benefit of getting more depth of field at the same aperture? Why require the use of the same aperture? For example, you typically shoot at f/11 using an MPE-65 on a 1.6X crop factor camera. A full frame shooter could get the same depth of field as you do by using a smaller [EDIT - larger!] f-number. As it happens if they too used an MPE-65 they couldn't reduce the aperture quite enough to match your f/11 for DOF, but if they used an f/22 or f/32 macro lens they could. Here too, I think some qualification is needed.

All true Nick -but they'd have to change the aperture and eat the diffraction penalty. Always trade offs.

Always trade offs for sure. In this case they would have changed the aperture so as to get the same DOF as you, so with the same field of view as you their trade off for getting the same DOF as you would be to increase their diffraction penalty to be the same as the diffraction penalty you have to eat.

If that were not the case, and FF did have an extra diffraction penalty compared to APS-C for a given field of view and DOF then you, using APS-C, would surely have an extra diffraction penalty compared to mFT, and even more so compared to 1/2.3". (I don't think that is the case of course, and I'd be surprised if you did, but I think that is where the logic of this particular APS-C vs FF argument leads.)

All true.

A m43 sensor is a good choice if all you carte about is getting the subject as large as possible in the frame. Is it the best choice for image quality? No...

And by the same token, wouldn't a full frame sensor be better than APS-C? And medium format better still? In which case, perhaps I should write "An APS-C sensor is a good choice if all you care about is getting the subject as large as possible in the frame. Is it the best choice for image quality? No...". Coming from a full frame user like me, I think that might be taken to be a bit condescending.

With the 80D I'm only shooting with one less stop of dynamic range than the 5D Mk IV, a full frame 35MP sensor.Since I'm not using AF or any other feature of the camera dynamic range is pretty much the only thing I care about. Noise is so easy to deal with in post that it's practically a non issue.

Would the 5D 4 still have better IQ? Sure. But I know several photographers that have both cameras and they shoot macro with the 80D.

As for intent: I'm never condescending in my posts, at least I don't intend to be. If you could Facetime with me, or Zoom chat, I think you'd have a much better impression of me. All too easy to read into what someone writes.

I think it is more complicated than simply "wanting to get the subject as large as possible in the frame", or that any particular sensor size is optimal for close-up/macro. As we both believe, there are always trade-offs.

Absolutely true. It all depends on what you're trying to accomplish and what you're willing to sacrifice to get it.

I agree. 100%.

junmoe62 wrote:

I would personally not call you nuts for saying that. If you understand that the fact of cropping 2x will reduce you picture‘s resolution by the same amount. The resulting framing of your cropped picture would be similar to what you would get with a 600mm lens. You would obviously lose 2x the resolution compared to shooting with a real physical 600mm lens and also emphasize the flaws of the lens.

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".

Totally agree with you!

That's what I was trying to say, but I don't think I presented it well.

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.

Once again you’re theoretically right, but practically I think this is largely dependent on the optical qualities of the lenses and the pixel densities of the sensors.

OK, I'll agree. Lots of factors at play.

Let’s stay in the theory and say we are in a perfect world (with Teletubies, rainbow unicorns and cotton candy clouds everywhere. My favorite place ever!! :D). We make a side by side comparison :

We shoot an optically perfect 60mm 1x mag lens @f2.8 on a perfect 20MP m43 sensor @ iso100

We shoot an optically perfect 120mm 1x mag lens @f5.6 on a perfect 20MP FF sensor @ iso400

both same technology, same subject and distance to subject.

At 1x the working distance won't be the same though, if the mag is the same. Even the depth of field will be different because the Fstop is not equal. Where already comparing apples and oranges...

So both systems are shooting at the same magnification, yet, which picture do you think will end up with the most details?

I'll pick full frame because even at ISO 400 the image is gonna have less noise.

It is interesting when you read the Wikipedia definition of magnification :

quote from Wikipedia : “Magnification is the process of enlarging the apparent size, not physical size, of something. This enlargement is quantified by a calculated number also called "magnification". When this number is less than one, it refers to a reduction in size, sometimes called minification or de-magnification.

Typically, magnification is related to scaling up visuals or images to be able to see more detail, increasing resolution, using microscope, printingtechniques, or digital processing. In all cases, the magnification of the image does not change the perspective of the image.”

It gets muddy once you get past the image that's projected onto the sensor.

Based on that definition I see 2 interesting things :

- If Magnification is the process of enlarging the apparent size, not physical size, of something. Does it mean that enlarging the apparent size thanks to the pixel density of the sensor be considered as magnifying, even though the magnification of the lens relatif to the sensor size is a fixed number?

Kinda had this discussion already. If I take a photo of a field of sunflowers that has a butterfly in the foreground and print the image billboard size so that the butterfly is now life size in the print is it then a macro photo?

- We can also see from this definition that the magnification of the image does not change the perspective of the image. Which shows once again that zooming, magnifying or cropping doesn’t affect in anyway the perspective.

Doesn't change the magnification either

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.

I totally understood your attempt John, absolutely no offense has been taken. I also told you in each and every of my posts that I wholeheartedly agreed with you, that you are totally correct (Except for the perspective thing) and I even thanked you many times for correcting the mistakes. Nothing has changed and I truly mean it!

The only point I was trying to make since the beginning concernes the fact that I don’t think it is very helpful nor meaningful enough to hijack each and every threads and turn them into super geeky techy fight.

Not my intent. But telling people that using a 2x lens on a m43 camera gives you 4x mag is extremely misleading.

I’m not implying that is what you do nor that is a habit of yours, but if you spent enough time in the m43 forum, you will see this kind of behavior is extremely common, to the point where it just becomes toxic. Everyone spending a minimum of their time in the m43 forum already witnessed that countless times I’m sure. One would be extremely unlucky (or should I say lucky :D) to miss on the equivalence talks in this forum!!!4

Looking at this forum has been like stepping into a time machine. Like I've said before we've had these discussions in the 1.6x crop factor community already and concluded that it's called "crop factor" and not "universal multiplier" for a reason...

I just think this kinds of endless boring talks just don’t really help anyone and actually Scare away many beginners and new comers. I know for a fact that it did for me for several years. And I can promise you that while writing this thread I was sure it will turn out that way!! I don’t know what’s going on on this forum, but if you have the very bad idea to associate the letter “E” and “Q” next to each others, a very strong chemical reaction will happen!! This thing is like nitroglycerine!! One drop is enough!! Boom!

Agreed.

I think spending more time on what’s actually going to improve the overall photographs (like lighting, composition, color science, how to approach the subject, how to get good diffusion and catchlights in the insects eyes,...) would be way more useful to everyone, especially beginners, than getting semantics right. Sadly you chose the latter... I mean, in all your posts in the thread you never ever referred once nor commented on the pictures, even though I invited people to do so in my original post and that I would have really been glad about it.

Actually that's not true, I did compliment you on the photos. But I also made it clear that a crop is a crop.

For example, it’s my first time posting on the forum, do you think your 2 first posts sound like a warm welcoming to the forum?! It felt more like passing an exam, and the teacher correcting the mistakes. It was only missing the score at the end! I’m not really sure that’s what most people willing to post on the forum are after, but I might be wrong...

Sorry, but that's gonna happen when you write a post that sounds like a tutorial and make mistakes...

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.

The thing is that I don’t think I’ve ever Implied that! For example, when I say “a 300mm F4 on a m43 body is roughly equivalent to a 600mm F8 on FF body“ I don’t think it means in anyway that a 300mm F4 on a m43 body is a 600mm F8 on FF body.

Anyways, in the end I think we are agree on the core thing, but we are just arguing about a different way of looking at things and we don’t put the cursor of the accuracy/approximation at the same level. You’re more on the tight & academic side, I’m more on the lose & field experience side... To illustrate my point I could see a talk between Mozart and Jimi Hendrix, with Mozart saying : “academic learning is key!!!” And Hendrix answering something like : “F@#$ that sh#$, bruh!!! Practice and experience is the answer!” :D.

To end this long answer, I really want to emphasize that I in no way attempted to bash you either and I really hope you won’t take anything personal.

Same!

You sound like a very nice and knowledgeable guy and I really hope we’ll be able to have friendly and constructive talks in the future! I mean it! (I just hope it won’t be on equivalence though!!! :D)

I wish you a nice day and happy shooting.

Regards,

Julien

Respect.

junmoe62 wrote:

gardenersassistant wrote:

junmoe62 wrote:

Now though, I’m wondering if you would still get the same result when changing you working distance. Because that’s what’s happening when you add a diopter on a lens. So while using the bare lens at it’s closest focusing distance, do you still get the same exposure than when using that same lens + the diopter At the closest focusing distance?

Yes.

I photographed a sheet of printer paper in natural light, using aperture priority with zero exposure compensation, using the same f-number and ISO for each shot. The camera used the same shutter speed in each case.

Ok! That’s good to know! Thank you!

So it also means that it seems to rule out the posItion relative to subject at a potential interference.

That’s interesting, because in my real world experience in using the M-250 on the 60mm f2.8, I’m seeing myself having to rise the power of the flash more often than not compared to the bare lens (I’m using a laowa twin head manual flash). I cannot say for sure, since I don’t really record every time I do it in the field, but that’s definitely the feeling that I have. Maybe that’s just because in the field the difference of framing induces the change in exposure (obviously, in real use case the scene isn’t as perfect as a flat blank surface)?!
Also, maybe the factor that might change the exposure might be that since my light source is on the camera, when I get closer, the lights get closer as well (or at least change their position), so it messes with the exposure?!

I think there are a number of factors. For example, when you add a close-up lens the framing will probably be different. This may cause a different proportion of lighter and darker areas in the frame, which may change the amount of light needed. The working distance will probably be different too, which will probably alter the distance between the subject and the flash heads. (I keep saying "probably" because I can think of exceptions to all of these.) With a different working distance the amount of light reaching the subject from the flash heads will be different. Also, the difference in working distance may mean that the flash heads are pointing less directly (or more directly) at the subject, which may alter the amount of light reaching the subject from the flash heads.

Here are four examples captured with a G80 and KX800 twin flash with a diffuser that spreads the light around quite a lot. The flash power, aperture, ISO and shutter speed were the same for each shot and the flash heads were in the same position for each shot.

Bare 60mm macro at 1:1, working distance around 80mm

60mm macro at 1:1 with Raynox 250, working distance around 35mm

Bare 60mm macro at 1:2, working distance around 125mm

60mm macro at 1:2 with Raynox 250, working distance around 50mm

In your experiment, I can imagine your light sources were fixed, am I right? That would make more sense to keep the light sources fixed to rule out that parameter.

Yes. The paper was illuminated from above with natural light from a roof window. The light was even and diffused because there was 100% cloud cover.

junmoe62 wrote:

John K wrote:

junmoe62 wrote:

I would personally not call you nuts for saying that. If you understand that the fact of cropping 2x will reduce you picture‘s resolution by the same amount. The resulting framing of your cropped picture would be similar to what you would get with a 600mm lens. You would obviously lose 2x the resolution compared to shooting with a real physical 600mm lens and also emphasize the flaws of the lens.

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".

Totally agree with you!

That's what I was trying to say, but I don't think I presented it well.

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.

Once again you’re theoretically right, but practically I think this is largely dependent on the optical qualities of the lenses and the pixel densities of the sensors.

OK, I'll agree. Lots of factors at play.

Let’s stay in the theory and say we are in a perfect world (with Teletubies, rainbow unicorns and cotton candy clouds everywhere. My favorite place ever!! :D). We make a side by side comparison :

We shoot an optically perfect 60mm 1x mag lens @f2.8 on a perfect 20MP m43 sensor @ iso100

We shoot an optically perfect 120mm 1x mag lens @f5.6 on a perfect 20MP FF sensor @ iso400

both same technology, same subject and distance to subject.

At 1x the working distance won't be the same though, if the mag is the same. Even the depth of field will be different because the Fstop is not equal. Where already comparing apples and oranges...

Yes you’re right, in my example the working distance would be different, my mistake.

But this shows that if you want to get the closest resulting pictures and shooting conditions with the 2 setups mentioned above, you’ll have to use a 2:1 mag lens on the FF. And I‘m pretty sure the 2 resulting pictures would be so similar to each other in every ways that you would be hard pressed to tell them apart. Now does it mean a perfect 60mm 1x mag lens @f2.8 on a perfect 20MP m43 sensor @ iso100 is a perfect 120mm 2x mag lens @f5.6 on a perfect 20MP FF sensor @ iso400? Definitely not! But I personally think it is close enough to get a rough idea of the results provided by those setups. I personally see the equivalence thing as a rule of thumb, not as an absolute truth. Once again, that’s just a matter of where you put your tolerance level.

I mean, if you really want to be picky, if someone tells you that he has the same 5DSR + MPE-65 combo than his neighbor, you could argue that he’s wrong! You would actually be right if you did, because the manufacturing tolerances would lead in absolute term to slightly different output. I’m pretty confident in saying that you would actually be able to see the output difference between the combo on the best side of the tolerance compared to the one on the worst side. Yet, would you question the claim of that guy having the same combo than his neighbor?

So both systems are shooting at the same magnification, yet, which picture do you think will end up with the most details?

I'll pick full frame because even at ISO 400 the image is gonna have less noise.

Oh really? I’m really surprised by this claim. I thought the potential theoretical difference between FF and m43 was 2 stops?!

If it had a difference, would it be that meaningful?

I’m not trying to argue there, I’m really interested in knowing what makes you say that.

You might be interested in this exercise I did in 2018, which included like for like comparisons of "equivalent" shots from a full frame Sony A7ii and a micro four thirds G80. The write-up is quite lengthy (running to 14 posts) and there was a lot of discussion, so I thought it might be helpful to provide an extract from the final "My overall impressions" section at the end of the top post in that thread.

In terms of the slight difference in noise in backgrounds, you may find it useful to look at this response from @Great Bustard which related the difference in noise to differences between the characteristics of the sensors being used.

My overall impressions [extract]

When capturing the same scene (shooting raw) with an A7ii and a G80 with the same DOF and shutter speed (to produce “equivalent” images), the results generally look rather similar. They look similar before noise reduction and sharpening is applied and they look similar after the same noise reduction and sharpening is applied to both images.

The major differences are that the backgrounds of the A7ii images tend to be very slightly noisier, while the clarity, detail and sharpness of the A7ii images is better in some cases. (For example see the response titled “Comparing the images - Scene 5”.) These differences are most apparent when viewing the images at the pixel height of the G80, 3400 pixels. When looking at my usual display height of 1400 pixels these differences (which are only visible in some scenes at 3400 pixel height) are sometimes still visible, and sometimes not.

The colours of the A7ii version can occasionally look richer compared to G80 colours that look a bit washed out. (See the response titled “Comparing the images - Scene 5”)

The A7ii handles deep shadow recover far better than the G80, which exhibited severe (I think unrecoverable) issues with noise, especially colour noise, with the deep shadow recovery test in this exercise. (See the response titled “Comparing the images - Scene 1”)

When capturing the same scenes with the A7ii using the same exposure as for the G80 (and the same DOF) the A7ii produces results which are significantly less noisy, with smoother looking backgrounds. The difference between these “equal exposure” shots and both of the other two shots is much larger than the differences between the other two shots. (See the response titled “A note on equal exposure” for more about equal exposure.)

However, using the same exposure means using an A7ii shutter speed four times longer and where the G80 (or the A7ii in equivalent mode) only just has a fast enough shutter speed the A7ii equal exposure shot can suffer from significant blur caused by subject movement and/or hand-shake. (For example see the response titled “Comparing the images - Scenes 9 and 10”)

junmoe62 wrote:

Thank you Nick for the link!

those are great resources once again! It must take you so much time and effort to put all these experiments and write ups together!! That’s really awesome to share that with the community! Big kudos to you.

Thanks Julien. I do these exercises primarily to better understand things that matter to me for my photography. Writing them up helps me think them through thoroughly, especially when I know (and hope) that one or two people may cast a highly critical eye over it. And sometimes someone may try very hard to prove me wrong if I'm going against their understanding, and arguing the case can be very helpful to me, either to convince me I'm right or to show me I am wrong and need to rethink/understand better. It's all quite selfish in a way.

Cheers,

julien