tupp

Late to the conversation here and haven't read all the replies.
I moved from my crop-sensor a6500 to a full frame Panasonic S1 for the better low light ability / increased dynamic range, and for the 10-bit 4:2:2 codec.
But that is because I shoot real estate and have to deal with ambient lighting. When shooting real estate videos, there often isn't time (or a budget) to set up lighting. So I often have a COUPLE of shots per video which are at the ISO 1600 to 3200 range.
Other times I am dealing with extreme levels of dynamic range.
The S1 does pretty well in these situations. Far better than the a6500.

Thanks for the link!
 
I doubt that he is talking about this exact issue.  Like most other folks who do equivalency tests, he likely limits his attention to mathematical DOF, and his tests use wider angle lenses and there is no delineation of the front and rear DOF limits with a lot of other detail thrown away or ignored.
 
 
I don't have time right now to read the linked page, but if the images shown are the extent of his comparison, his tests are invalid.  He does not show how the limits of DOF are delineated.  He seems to be using wide angles focal lengths, and I can see a difference in one of the images with just a glance.

There is an interesting post from cinematographer Steve Yedlin talking about this exact issue. As far as he's concerned, there is no unique 'look' to larger formats unless using a different format somehow forces you to set up your camera differently. https://www.yedlin.net/NerdyFilmTechStuff/MatchLensBlur.html
 
He has some pretty rigorous testing to go with it.

Well, you've convinced me that there's something worth considering there for sure. I had always conceived of the equivalence debates as being along the lines of flat-earthers etc 🤣
But now I see that for some it's just about a level of complexity and possibly even bokeh connosseurship.
For my purposes, these differences are so rarefied as to be irrelevant. However, the idea of testing for them is interesting. How about a test where you simulate a small sensor by using a center crop from a full frame stills camera? Like this:
Full frame
200mm, f7.1
Simulated 4x crop sensor
50mm, f1.8
These would be different lenses. I could do this (when I have time) with a Canon 50 1.8 and Sigma 70-200 f2.8 and use ACR to correct for lens aberrations. Or instead with an OM Zuiko 50 1.8 and OM Zuiko 200mm f4 (possibly similar primes? But can't correct for aberrations)
Would 4x be enough to show a difference?
I realise you're dealing with a lower megapixel image from the central portion of a wide open lens for the simulated 4x so the image will be softer.  Would these variables make the test invalid?

The quotation marks that I employed imply something else.  I'm saying that refractive optical elements can affect focus and the focus range, and, additionally, that there are general tendencies, advantages and problems inherent in refractive optics designed for larger formats and likewise with refractive optics designed for smaller formats.  Of course, there are exceptions and some lenses for smaller formats possess some of the qualities generally found in larger format lenses, and vice versa.
 
 
There is consistency, but there is also seems to be more than one variable at play, so there is some complexity.
 
I would describe the look of larger formats as generally having a flatter and more "solid" focus plane with a faster "rolloff" at the DOF limits, but with a smoother and better resolved "macro-contrast" outside of the DOF limits.
 
 
There is not a huge difference between FF and M4/3.
 
Using a speedbooster or focal reducer can allow the qualities of the larger format optics to be captured on a smaller format.
 
 
The dramatic discrepancies between the two images shown above are not due to any tendencies inherent in different sized formats.  My guess is that the DOF was not equivalently matched, plus the 1-inch camera likely had a built-in zoom lens (which can look/behave different than a prime) and excessive in-camera sharpening could have been enabled.
 
There are a lot of variables that need to be controlled in such comparisons, otherwise the tests are invalid.

This implies that you maintain that there is a look inherent to a format, independent of variations between lenses. If so, it should be consistent as format size changes and it should be describable. How does the look of small format compare to the look of a larger format, at equivalent focal lengths and apertures?
I'm just interested here, as I use DOF calculators to help my understanding when moving between FF, micro 4/3 and speedboosted micro 4/3. But I also see a huge difference in the images posted, which I would not have expected.
 

Probably not.. but it is a camera designed to do both regardless of how you rig it. Like my GH5 rigged to a gimbal is still a hybrid designed for a Photographer to use.  But no one would shoot photos that way.  At least, I hope not. 😆

Oddly enough no.  My main point is that smaller sensors can cost more than fullframe.  Having more money doesn't necessary equate choosing fullframe.  Its as much down to personal choice of what you need or want to use - hybrids, smaller cameras, larger cinema cameras.  
I wouldn't buy a Sony as I've never liked using or editing their footage.  And to be honest, I don't shoot enough photos to need a camera that does both.  Maybe one fullframe I am thinking about to cover those small jobs where I do.  Mostly though, I want to stick to dedicated video cameras.
 

I certainly can see what you're talking about in the areas you've highlighted. It's very clear.
But if you plug equivalent settings into a DOF calculator you get the same amount of DOF for both, according to the calculator. This is the theory, and it depends on certain assumptions regarding circle of confusion that I won't pretend I understand in depth.
So is it fair to say that your position is something like this:
"Even though DOF calculators show that the theoretical DOF of equivalent shots is the same, in practice there is an observable difference in how DOF is rendered between equivalent shots"?
If so, and if I understand you correctly, that would mean that a DOF calculator is showing us 2 points on the DOF continuum, the point of near focus and the point of far focus, and these are the same for both formats if the focal length and aperture is equivalent. But it's not telling us anything about the DOF characteristics elsewhere on the continuum, which is noticeably different.
That's certainly very interesting and worth investigating. I think for most people it's enough to know that they can match the field of view precisely using equivalence theory, and that the DOF is "the same" according to its assumptions. But others may notice and be very interested in differences in DOF behaviour that's not described by equivalence theory... if what you say is true! So we would be talking about a kind of DOF rolloff, which is shorter on larger formats and longer on small formats, according to equivalence sceptics.
Is this understanding correct @tupp?
 

Sad day .  To find out I’ve only been using parts of my images for years?  Bummer. 

Thats odd as S35 cinema cameras cost a lot more than many fullframe hybrids..   and I'd rather have the money to buy a C300, a Red Komodo or an URSA 12k over a fullframe A7C,  or any other fullframe hybrids for that matter... 😆😆

To test this you could use:
standard 16mm, Bolex (Kern Paillard 10mm at f/1.8
4/3rds, 17mm at f/3.2
APS-C (Nikon DX), 22mm at f/4
Full Frame, 34mm at f/6.3
8x10, 256mm at f/45
The 16mm would have to be wide open and the 8x10 would have to be completely stopped down (my 8x10 270mm is f/4.4 - 45)
This is according to this calculator:
https://www.pointsinfocus.com/tools/depth-of-field-and-equivalent-lens-calculator/#{"c":[{"f":13,"av":"8","fl":50,"d":3048,"cm":"0"}],"m":0}
Damn it you’ve got me doing it now!
Like Oliver Hardy and his taxi driver getting involved in Stan Laurel’s jigsaw puzzle,
and they miss his wedding ceremony…

The differences are quite minor to the point of it proves theory and practice match to me, even in my crappy comparison between a more than 35 year old FF prime and a much more modern 1 inch sensor zoom.   
That you can not seem to understand that tells me you have visited that river and drunk from it way too many times!
Unless you CAN post proof that to setups to match exactly will not give the "same" photo, there really IS no purpose in continuing and if you do want to post more, just imagine me posting a reply that says I disagree.
Thank you.

So, if there is no way to get a close enough match in focal length for an equivalency test, how can any of the equivalency tests made so far be accepted as valid?
 
Actually, there are a lot of 16 and Super 16 prime lenses.  Start with that format as the smaller camera.  There are also plenty of 8"x10" lenses.  It shouldn't be too difficult to use the formula behind the equivalency principle to calculate a close enough match with lenses for those two formats.  A little cropping of one of the images is okay, but a zoom lens is not okay.
 
 
Well, everyone has a right to their view.  You evidently don't see the stark differences that I can see with just a glance at the full frame and 1-inch images.
 
Perhaps another comparison method of the two images would make the differences more apparent.  Here is a gif of the two equivalent images alternately flashed at one-second intervals:

Do you not see in the area outlined in red how the distant white building exhibits sharp edges in the 1-inch image, while it is much softer in the full frame image?
 
Likewise, inside the green outline, do you not see how the distant trees are significantly blurry in the FF image, yet we can see their individual branches in the 1-inch image?
 
Closer to the camera, within the blue outline do you not notice how the vertical supports on the fence are softer in the FF image and sharper in the 1-inch image?
 
From your description, I wasn't completely sure which image came from which camera, so please correct me if I got the format labels wrong.  Regardless, there is a substantial difference in the look and DOF of the two images.
 
 
I actually offered to collaborate on an equivalency comparison with an EOSHD poster who is a staunch proponent of the equivalency principle and who happens to reside in my town.  The equivalency poster refused my offer.
 
I would not do such a test without an equivalency supporter present to oversee and certify the matching of the DOF.  If I did the test alone, without such certification and if the results showed a dramatic difference in look/DOF, folks would just claim that I did something wrong or that I intentionally manipulated the images.   Several times in this forum I have pointed out prominent discrepancies in DOF/equivalency tests and those differences were dismissed as unimportant or ignored as unavoidable testing "inaccuracies."  I am not going to go through all the effort to do a proper comparison just to have the findings rejected outright.
 
 
I never disagreed with Caldwell regarding perspective.  Certainly, perspective is determined by the distance of the camera/observer from the subject, but there are exceptions to that rule, depending on how one defines "perspective."
 
However, perspective has little to do with the question of whether different sized formats give contrasting looks or exhibit differing DOF.
 
By the way, Caldwell agreed that there is more to DOF than the the factors/variables found in the DOF formula (which is the basis for the equivalency principle).

Strongly disagree here.  Even if #1 and #3 match according to the "equivalence principle," they won't look the same.
 
The DOF on a Super 16mm camera can be made to "mathematically" match the DOF on an 8"x10" camera, but they will not look the same.  Furthermore, in the same scenario, the rate and manner in which the DOF "rolls off" will differ between those two different formats.

All I will say is if you want to prove an exact match would not give the same photos, do it yourself but again, when YOU do, make sure you have multiple lenses and cameras for each format otherwise I will just point out the differences why the equipment is not going to be an exact match and say it is invalid.
ALL the photos I have seen about this prove to my satisfaction the theory matches reality and even my crappy photos are close enough to prove that.
Beyond that I disagree.
Thanks for playing,.

That would depend on the lenses but if someone really went to the trouble of trying for an EXACT match they would need to take into account everything including each individual lenses characteristics, and that would be almost as difficult to do with two M43 lenses of the same focal length as it would with a Pentax Q and a Mamiya 7 with a digital back (assuming you can find lenses to match).
I am satisfied the photos I posted show enough similarity to prove my point and just to satisfy myself I DID test with my Sony Zeiss 55 1.8 VS the RX100 iv Sony Zeiss lens  and it is as i suspected a closer match still.....now since it is not an EXACT match and was also just a quick and dirty comparison, there is zero point posting because you would just say it is different.
Feel free to set things up to match theoretically lenses of two (or more) different formats but include a couple of lenses for each format used....If you do that, I am sure the photos would be the same, if you are not, then maybe you should disprove it...
Lastly regards Dr Caldwell,
"Do the experiment properly and you'll find that the perspective is the same.  Surely you must have heard countless times before that perspective depends only on the subject distance.  This is a truth that you shouldn't ignore.  More precisely, perspective depends on the distance from the subject to the entrance pupil of the lens.  For this reason, the entrance pupil is sometimes called the center of perspective. "
I disagreed with you in that thread and I disagree with you in this one hence why this is pointless now.
Enjoy what you use and use what you want!

Yeah, the problem with equivalence tests is finding or having the equivalent lenses to not prejudice the FF camera.
Having to have the FF at f4 because the APS-C had to be at f2.8 and the MFT with the SB could be f2  is not doing the FF any favours.
Matching the focal lengths also make it a challenge without using a zoom as well of course as at least they maintain the same contrast and colour for each camera.
I'm trying to think about which set of cameras and primes that could be used for be a totally accurate test if someone wanted to do it properly and its a tricky ask to get exact matches.
 

@ZEEK occasionally posts in this forum!

https://www.magiclantern.fm/forum/index.php?topic=23041.msg216899#msg216899
Background: user TheBilalFakhouri has unlocked correctly framed real time preview for EOS M and Danne has ported it to 5D3. Previously, Magic Lantern high res modes had a preview image that had either correct framing but in unusably slow frame rate black and white or real time colour preview with wrong framing. 
Now, however there is high res, real time preview with correct framing.
Kind of fun to try if you already own one of the supported cams 😁

@ZEEK where are you man? Your level of expertise is required over here :- )

Dang, now Eoshd is talking again. Beautiful nerdy threads. Keep em coming! I want some underdog beauty: GH4 or FZ2000 with external 10bit. GH4 with a YAWG and battery solution. Software mods, hardware mods, shitty rigs, super rigs- keep em coming, the happy bee is humming! EOS M super 8 raw thread was one of my favorites of the last two years. Would love people to shoot some recreational short pieces with these nerds´dream cams. Unfortunately I have not done the walk yet to be called a nerd. Maybe if I get to mod my Konica mount zoom lens to EF.
Edit: that zeek youtube link above seems like a nerds entertainment dream. Thank you very much @stephen

Thanks for the reminder of that thread.
That thread alone is reason enough to not proceed any further since people would argue with the bloke who designed the Metabones speedbooster as well as one of the best lenses ever (Coastal Optics 60mm f4),there is zero point in a non entity like me trying any further..
 

IF I spent ages and ages, setting it up and trying for an exact match, the photos WOULD look extremely close (24 at f4.8 vs 8.8 at 1.8) even with this apples to fish comparison.
Again though why on Earth would I want to?
Given I used a more than thirty year old prime against  a much more modern fixed lens zoom on a tiny 1 inch sensor camera and to me, the photos are pretty similar (with errors down to me), I think I proved my point.     I could have also used my Sony Zeiss 55 1.8 (at f8 VS 2.8 also a Sony Zeiss lens) and it would be a closer match.
Lastly, if you compared different M43 lenses against each other at the same focal length and/or different M43 cameras the look would not be the EXACT same as no two of ANYTHING will be exactly the same.

FWIW, I did a very quick basic comparison between MFT, APS-C and FF at a couple of focal lengths a few years ago on here and the differences in those specific limited instances with zoom lenses to create the correct equivalent focal lengths were marginal.
A more thorough test at different distances using primes would possibly yield more telling differences but I got bored.
Close enough for jazz as we would say.