Medium format look – a topic debated at nauseam but now with a visual twist

[Charles_S]

What follows is a pre-amble to a visual test about of how to demonstrate what “the medium format look” means to me (YMMV).

A while ago I expressed my view about my view of what creates the "medium format look" or what makes the MF format different from samller sensor formats which got lost in the ensuing shuffle and one-upmanship on this board.

Here goes again:

“The MF look is in the interplay between sensor size (or film size), focal length, FOV and DOF. For a given focal length, a larger sensor delivers a wider FOV which allows you to move in closer to your subject (for the same framing as an FF would give you), which gives you a narrower DOF, but above all stronger focus fall-off or background blur. The bigger the sensor (or film), the stronger the effect. The Fuji sensor size cannot deliver the same degree of effect as say a 6x7 film camera for that reason. It is physics. If you compare to FF, the effect is there, but might be too small to notice.”

Let’s break this statement in pieces:

• What is my definition of the MF look?. I shoot mostly portraits, and what matters to me is the way I can play with focus and focus fall-off on the subject and how it is isolated against the background. In my experience, there is an observable difference between sensor/film formats. A visually easy reference point in this regards is the work of Martin Schoeller (there are others of course). As far as I understand it from the BTS videos that I have watched, he shoots his close-in portraits on a Mamiya 6x7 (which doesn’t prove that this is the only way you can get this look).

• From a AOV / DOF perspective, it is easy to calculate the equivalent focal lengths and f/stops required to obtain the same values between different sensor / film formats and lenses. No argument there, it’s just simple math. In my experience, in particular for flat-ish subjects at medium or farther distances, it is hard to distinguish between camera formats as many people on this forum have argued and shown.

• Besides AOV and DOF, there is a third dimension, which is the focus fall-off, which was the point I was trying to make as another dimension that distinguishes larger sensors from smaller ones, which got lost. The interplay between AOV / DOF and focus fall off is different between formats because the subject distance is different and the focal length is different. So on the “in-focus” area of the subject it makes no difference, but you can tell there is a difference by looking outside of the area in-focus. This effect is particularly strong at shorter subject distances, and far away backgrounds. This point can also be made mathematically by calculating blur at a distance from the subject in focus. Again, it’s math, not much to argue.

• My statement does not consider bit-depth, pixel size etc, which admittedly also play a role, as pointed out by a number of others

Link to the websites I used for the calculations that accompany my test:

Depth of Field (DoF), Angle of View, and Equivalent Lens Calculator • Points in Focus Photography

depth of field - Does amount of background blur change with focal length given equal framing? - Photography Stack Exchange

Rather than diving into the debate again with verbal arguments, it seemed easier to illustrate the difference with a simple experiment. Simply put; if there is such a thing as the MF look as I expressed it, you should be able to see it in the experiment. If it is so subtle that it isn’t visible, it is not worth debating. The image at the bottom of this post is one of the image comparisons of the test described below.

The test has been designed to show that there are circumstances in which it is visible. Whether these circumstances are relevant to the readers’ photography is another matter.

The comparison I made is between an X-Pro 2 (APS-C) and an GFX 50s (Medium-ish format). I chose to use a Canon 40mm STM and a Canon 70-300L on adapters for the experiment. These budget-ish lenses are not stellar performers by any means, nor do they have extreme wide-open aperture values. It eliminates a discussion about lens manufacturers, lens designs, coatings etc. It is also happens to be the gear that i can mount on both cameras that I have at-hand.

I am very aware that there are a number of shortcomings in this experiment, it does not stand-up to scientific scrutiny and is not intended to do so. For instance, the test does not consider Mpix count, bit depth, edge performance and other aspects that have been advanced as advantages of MF. It shows only what I would call the geometric aspects of comparing the formats. Since the cameras and sensors are dated, it does not consider the progress in technology since made in particular with FF cameras. It therefore does not answer the question whether for instance an R5 is a "better" camera than a GFX50s even for this particular use-case. I would be interested to seeing the comparison in a similar set-up.



The results

Since there are more images to look at than is practical to post in this thread, I have put the results in a pdf (with the Mod's permission). The document also contains the calculations for each comparison.

https://1drv.ms/b/s!AtJxl9Z1DHNsjNER3tW4f6Z90IWudA?e=oU4Skk

Predictably, the test showed:

1. The larger GFX sensor allows you to get closer to the subject (at the same focal length and same FOV), which leads to a more blurred background (test 3 and 4), and by extension what I call faster focus fall-off
2. At the same AOV and DOF settings (meaning the perspective on the subject and the DOF on the subject are the same), the background blur is stronger with the larger sensor, and by extension the focus fall-off. (test 5 and 6)

Whether this is enough to justify the additional cost and inconvenience of owning a MF system is an entirely different matter

Looking forward to your comments.



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[Michael Floyd]

Hmmm.

I'm quite honestly open minded about this, however your PDF hasn't made a clear point to my reading.

Reading your stack exchange link, I could accept that infinity background blur is greater with a longer focal length despite all else being such that the AOV and DOF are equivalent, after I test it for myself. I see that you've tried to show this in your PDF, although the exposure in the backgrounds is so different that I can't see the comparison clearly, unfortunately.

I applaud your effort though, and look forward to the responses.

 

[Bashir Lunat]

Thank you. MF look is not mythical.

 

[DavidMillier]

Your argument appears to be that DOF reduces when you focus closer. Hardly newsworthy!

 

[Hamiltionian]

Since there are more images to look at than is practical to post in this thread, I have put the results in a pdf (with the Mod's permission). The document also contains the calculations for each comparison.

https://1drv.ms/b/s!AtJxl9Z1DHNsjNER3tW4f6Z90IWudA?e=oU4Skk

Predictably, the test showed:

1. The larger GFX sensor allows you to get closer to the subject (at the same focal length and same FOV), which leads to a more blurred background (test 3 and 4), and by extension what I call faster focus fall-off
2. At the same AOV and DOF settings (meaning the perspective on the subject and the DOF on the subject are the same), the background blur is stronger with the larger sensor, and by extension the focus fall-off. (test 5 and 6)

Whether this is enough to justify the additional cost and inconvenience of owning a MF system is an entirely different matter

Looking forward to your comments.

Once you scale the images to be the same output size, aren't these equivalent amounts of background blur? i.e, 90/40 ~ 579/286? If I am looking at the comparison image you post above, the amount of background blur looks identical to me.

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[JimKasson]

Perform some equivalent tests, please.

Equivalence

 

[Charles_S]

Once you scale the images to be the same output size, aren't these equivalent amounts of background blur? i.e, 90/40 ~ 579/286? If I am looking at the comparison image you post above, the amount of background blur looks identical to me.

Here are the raw files:

https://1drv.ms/u/s!AtJxl9Z1DHNsjNEcqigq32dW8CVZSQ?e=lbGf8x





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[Charles_S]

Perform some equivalent tests, please.

http://www.josephjamesphotography.com/equivalence/

What do you expect the outcome to be ?

 

[JimKasson]

Perform some equivalent tests, please.

http://www.josephjamesphotography.com/equivalence/

What do you expect the outcome to be ?

That many of your assertions will be disproven. DOF, perspective, diffraction will all be the same. Warning: these tests are not easy to conduct properly.

 

[NAwlins Contrarian]

What follows is a pre-amble to a visual test about of how to demonstrate what “the medium format look” means to me (YMMV).

A while ago I expressed my view about my view of what creates the "medium format look" or what makes the MF format different from samller sensor formats which got lost in the ensuing shuffle and one-upmanship on this board.

Here goes again:

“The MF look is in the interplay between sensor size (or film size), focal length, FOV and DOF. For a given focal length, a larger sensor delivers a wider FOV which allows you to move in closer to your subject (for the same framing as an FF would give you), which gives you a narrower DOF, but above all stronger focus fall-off or background blur. The bigger the sensor (or film), the stronger the effect. The Fuji sensor size cannot deliver the same degree of effect as say a 6x7 film camera for that reason. It is physics. If you compare to FF, the effect is there, but might be too small to notice.”

The claims were nonsense before, and remain nonsense. In addition to the link Jim K. already posted, see my replies in the prior thread at:

https://www.dpreview.com/forums/post/66458033

and

https://www.dpreview.com/forums/post/66458679

The whole premise that any sensible photographer would use the same focal length for different sensor sizes is ridiculous! If you want to compare an X-Pro 2 and an GFX 50S, then you need the focal length on the GFX 50S to be twice that of the focal length on the X-Pro 2.

Predictably, the test showed:

1. The larger GFX sensor allows you to get closer to the subject (at the same focal length and same FOV), which leads to a more blurred background (test 3 and 4), and by extension what I call faster focus fall-off

If you have a larger sensor but use the same focal length, you necessarily do not have the same field of view! Field of view is a function of the ratio between the sensor dimensions and the focal length; it can be expressed an an angle (diagonal) or two angles (horizontal and vertical). Just because you can make one subject (a head or whatever) occupy the same fraction of the image does not mean the field of view is the same; what's captured in front of and behind that subject will differ.

 

[highdesertmesa]

Perform some equivalent tests, please.

http://www.josephjamesphotography.com/equivalence/

What do you expect the outcome to be ?

That many of your assertions will be disproven. DOF, perspective, diffraction will all be the same. Warning: these tests are not easy to conduct properly.

One of the easiest ways to debunk these assertions is to shoot two shots of the same scene from the same position with the GFX – one in full 44x33 and one in 35mm crop mode. This rules out all sorts of variables like lens and sensor differences.

Differences are minor:

1. 44x33 is a wider FOV – 35mm is a more narrow FOV
2. No change in bokeh
3. Very minor change in perceived bokeh due to changes in FOV (similar to how the Brenizer method works but on a scale so small it makes almost no difference to the outcome).

So why do so many get this wrong? Because many photographer's idea of equivalence is based on maintaining equivalent composition and therefore changing the camera position or focal lengths between shots.

 

[Charles_S]

So why do so many get this wrong? Because many photographer's idea of equivalence is based on maintaining equivalent composition and therefore changing the camera position or focal lengths between shots.

I think we are talking about the same thing. You see it as "getting it wrong" I see it as how I can use MF differently and thereby creating different results.

 

[Charles_S]

The whole premise that any sensible photographer would use the same focal length for different sensor sizes is ridiculous!

This is not what i was asserting. The images were included to show the difference.

If you have a larger sensor but use the same focal length, you necessarily do not have the same field of view! Field of view is a function of the ratio between the sensor dimensions and the focal length; it can be expressed an an angle (diagonal) or two angles (horizontal and vertical). Just because you can make one subject (a head or whatever) occupy the same fraction of the image does not mean the field of view is the same; what's captured in front of and behind that subject will differ.

We are talking about the same thing. The site I used for the calculation expressed it as FOV. Possibly a semantic error.

 

[JimKasson]

So why do so many get this wrong? Because many photographer's idea of equivalence is based on maintaining equivalent composition and therefore changing the camera position or focal lengths between shots.

I think we are talking about the same thing. You see it as "getting it wrong" I see it as how I can use MF differently and thereby creating different results.

If your contention is that you can use an MF camera one specific way, and a smaller format camera another way, and get different images, I won't argue with you. I will point out that you can use an MF camera one specific way, and the same camera another way, and get different images

 

[highdesertmesa]

So why do so many get this wrong? Because many photographer's idea of equivalence is based on maintaining equivalent composition and therefore changing the camera position or focal lengths between shots.

I think we are talking about the same thing. You see it as "getting it wrong" I see it as how I can use MF differently and thereby creating different results.

It's valid to say you prefer the look of an image created by changing the camera position or focal length, which is required by changing sensor size formats to maintain the same composition – but it doesn't fit the definition of equivalence.

It's a bit like comparing images taken at different resolutions but comparing them at different print sizes. Yes, it's a valid way to compare if you plan on taking advantage of the higher resolution by making larger prints – but it's not an equivalent test.

 

[JimKasson]

Perform some equivalent tests, please.

http://www.josephjamesphotography.com/equivalence/

What do you expect the outcome to be ?

That many of your assertions will be disproven. DOF, perspective, diffraction will all be the same. Warning: these tests are not easy to conduct properly.

One of the easiest ways to debunk these assertions is to shoot two shots of the same scene from the same position with the GFX – one in full 44x33 and one in 35mm crop mode. This rules out all sorts of variables like lens and sensor differences.

Good idea, but not easy to do right.

Testing for the MF look - the last word

There is a recurring theme in many Internet fora that there is a “look” to medium format (MF) images apart from their generally higher acutance and detail, even when shot with lenses and settings that are equivalent to their full-frame (FF) counterparts. The claim is that the look is so strong...

blog.kasson.com

Differences are minor:

1. 44x33 is a wider FOV – 35mm is a more narrow FOV
2. No change in bokeh
3. Very minor change in perceived bokeh due to changes in FOV (similar to how the Brenizer method works but on a scale so small it makes almost no difference to the outcome).

So why do so many get this wrong? Because many photographer's idea of equivalence is based on maintaining equivalent composition and therefore changing the camera position or focal lengths between shots.

 

[Charles_S]

Perform some equivalent tests, please.

http://www.josephjamesphotography.com/equivalence/

What do you expect the outcome to be ?

That many of your assertions will be disproven. DOF, perspective, diffraction will all be the same. Warning: these tests are not easy to conduct properly.

This can be done through math, or am I mistaken ?

 

[highdesertmesa]

Perform some equivalent tests, please.

http://www.josephjamesphotography.com/equivalence/

What do you expect the outcome to be ?

That many of your assertions will be disproven. DOF, perspective, diffraction will all be the same. Warning: these tests are not easy to conduct properly.

One of the easiest ways to debunk these assertions is to shoot two shots of the same scene from the same position with the GFX – one in full 44x33 and one in 35mm crop mode. This rules out all sorts of variables like lens and sensor differences.

Good idea, but not easy to do right.

https://blog.kasson.com/gfx-50s/testing-for-the-mf-look/

Sure, since there are ways to skew the test one direction or the other – for example, using a long lens like the GF 250 wide open on a close target versus a wide lens like the GF 23 stopped down at infinity.

Further complicating any comparison is the change in the ratio of the format. Even moving down from 35mm to micro 4/3 gives a change in look that may favor the smaller format if you like 4:3.

Differences are minor:

1. 44x33 is a wider FOV – 35mm is a more narrow FOV
2. No change in bokeh
3. Very minor change in perceived bokeh due to changes in FOV (similar to how the Brenizer method works but on a scale so small it makes almost no difference to the outcome).

So why do so many get this wrong? Because many photographer's idea of equivalence is based on maintaining equivalent composition and therefore changing the camera position or focal lengths between shots.

 

[koweb]

What follows is a pre-amble to a visual test about of how to demonstrate what “the medium format look” means to me (YMMV).

A while ago I expressed my view about my view of what creates the "medium format look" or what makes the MF format different from samller sensor formats which got lost in the ensuing shuffle and one-upmanship on this board.

Here goes again:

“The MF look is in the interplay between sensor size (or film size), focal length, FOV and DOF. For a given focal length, a larger sensor delivers a wider FOV which allows you to move in closer to your subject (for the same framing as an FF would give you), which gives you a narrower DOF, but above all stronger focus fall-off or background blur. The bigger the sensor (or film), the stronger the effect. The Fuji sensor size cannot deliver the same degree of effect as say a 6x7 film camera for that reason. It is physics. If you compare to FF, the effect is there, but might be too small to notice.”

The claims were nonsense before, and remain nonsense. In addition to the link Jim K. already posted, see my replies in the prior thread at:

https://www.dpreview.com/forums/post/66458033

and

https://www.dpreview.com/forums/post/66458679

The whole premise that any sensible photographer would use the same focal length for different sensor sizes is ridiculous! If you want to compare an X-Pro 2 and an GFX 50S, then you need the focal length on the GFX 50S to be twice that of the focal length on the X-Pro 2.

Predictably, the test showed:

1. The larger GFX sensor allows you to get closer to the subject (at the same focal length and same FOV), which leads to a more blurred background (test 3 and 4), and by extension what I call faster focus fall-off

If you have a larger sensor but use the same focal length, you necessarily do not have the same field of view! Field of view is a function of the ratio between the sensor dimensions and the focal length; it can be expressed an an angle (diagonal) or two angles (horizontal and vertical). Just because you can make one subject (a head or whatever) occupy the same fraction of the image does not mean the field of view is the same; what's captured in front of and behind that subject will differ.

Following this discussion with interest...

As to your comment above that I've highlighted - didn't the OP already do what you suggested they do and use 2 different focal lengths? Or am I confused?

 

[MercedRiver]

When I used film I could see the medium format look because my 6x9 transparencies were so much larger than my 35mm. Now I can get the "medium format" look using micro four thirds and a quality lens. Today noise removal is so easy if it is even needed. Sorry, I couldn't resist poking at the hornet nest.