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2 hours ago, Jay60p said:

A few thoughts on this topic:

1) I would have expected this equivalency theory would have been tested more reliably by still photographers at the numerous

photography forums long ago. They use a much wider range of format sizes than the video people here at EOSHD.

If not, it could be there is just too many variables to control, or no consensus on the methods to use.

 

2)  I would suggest using a 4x5 sheet film camera (8x10 is at $15 a shot!) and limit the test to manual lenses.

Mount all lenses on a 4x5 lens board and take a 4x5 shot for each, to be scanned for viewing.

This way the camera does not change, the sensor does not change, no digital transformations are done in camera.

The different lenses would have different size image circles in the 4x5s, so would be of different resolutions,

but that should not effect the depth of field comparisons much.

 

I did look at the SLR primes with the Turbo II speedbooster. It shrinks the first fringing seen, but it includes more of the edges of the

image circle, with more CA, so overall the fringing looked the same. It really is not a big problem, in video it will never be noticed unless

you look for it, it's more of a problem in still photos.  I use these SLR primes for stop-motion and time lapse, where you don't want any

communication with the camera that changes the lens settings.

 

Here is a review of my favorite Fuji lens that includes comments on the in-camera corrections (CA, vignetting, distortion) for anyone

unfamiliar with this: https://opticallimits.com/fuji_x/887-fuji1024f4ois?start=1

 

My question is, what about the third party lenses? Do the mirrorless cameras generally apply in-camera corrections to

Sigma, Tokina, Tamron, that come in their lens mounts?

 

 

 

 

1) Equivalence theory HAS been tested and is accepted by the majority of photographers and scientists.      Most accept it even though no one has done an EXACT match (IE the photos LOOK very similar but someone will always point out a tiny difference) to the satisfaction of SOME but the deniers have never shown evidence that it is wrong either.

The problem in getting an EXACT match is you would have to scale the equipment for an EXACT match and that would be near impossible.       To the point the EASIEST way might be to build from scratch very simple low element number formulas that test this (but may not be great images).

There ARE science and technology forums on photography on various sites, so much better to ask in those rather than old format warriors on a video forum.

2) Nah, it would work for me but there will still be tiny system differences (lens formula ETC) that way which again to me would easily explain tiny difference in the photos but not others.

Remember, focal reducers do not change cameras, they change lenses so everything else still applies (some lenses have been MADE by tacking a focal reducer group onto an otherwise different lens).

Third party lenses CAN apply corrections but it depends.

Sony for example opens its mount to other manufacturers and M43 is an open mount too (they have to sign confidentiality agreements.

Canon and Nikon do not and the likes of Sigma have to reverse design.

Even my Canon EF lenses on my A7s  report the EXIF but the lenses get recorded as different Sony lenses so it MIGHT be correcting things but doing it as if it is a different lens though it still might be doing it right.

Then again, most of my Canon lenses are older that need less correction (or none).

In camera correction is not necessarily a bad thing as it means they can make lenses better in other areas (or cheaper or both).

My old Canon EF 20-35 2.8 L is probably better corrected than its great great great grandson (the 16-35 2.8 L iii) but the newer lens is a MUCH better lens.     I would love to do a comparison to see how they both go adapted to my Sony but the cost to experiment is far to high.

Olympus M43 lenses are some of the MOST corrected in camera and yet they are still extremely nice (yet not so long ago the 43 DSLR lenses were made large enough to cover APSC (at least in some cases) and would hardly have needed any correction.

Sony E probably corrects for vignetting which probably explains why DXO  often shows FF E mount lenses with the F stop and T stop being the same.

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

You must have a very large penis. 

can i get you boys dueling pistols for xmas ? then we can settle it once and for all 🙄

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Just looked at the EXIF for my Sigma 150 2.8 macro in Canon EF mount adapted to my E mount camera and it reports as being an 18-280 3.5-6.3 lens (everything else that matters is correct). 

I THINK (no evidence either way) it is correcting vignetting slightly.

Mine is an older first generation A7s so I do not think it corrects as many things as newer cameras but again, that is yet to be confirmed.

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5 hours ago, noone said:

In camera correction is not necessarily a bad thing as it means they can make lenses better in other areas (or cheaper or both).

Yes, it is a very good thing in the Fuji lenses. That's why I was asking about third party lenses, if they don't get corrections that puts them at a disadvantage.

And I wonder where a particular lens's correction information is stored, in the lens firmware or the camera firmware? Just curious.

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On 9/23/2020 at 9:09 AM, Jay60p said:

A few thoughts on this topic:

1) I would have expected this equivalency theory would have been tested more reliably by still photographers at the numerous photography forums long ago.  They use a much wider range of format sizes than the video people here at EOSHD.  If not, it could be there is just too many variables to control, or no consensus on the methods to use.

The reason why we don't have a proper test of DOF equivalency from still photographers (nor from cinematographers) likely doesn't involve involve the number of variables.  The true reason would probably require some philosophizing.

 

 

On 9/23/2020 at 9:09 AM, Jay60p said:

2)  I would suggest using a 4x5 sheet film camera (8x10 is at $15 a shot!) and limit the test to manual lenses.

Mount all lenses on a 4x5 lens board and take a 4x5 shot for each, to be scanned for viewing.

This way the camera does not change, the sensor does not change, no digital transformations are done in camera.

The different lenses would have different size image circles in the 4x5s, so would be of different resolutions,

but that should not effect the depth of field comparisons much.

It probably would not be wise to shoot DOF/equivalency comparisons using the same emulsion for different formats.  The smaller format on the same emulsion could appear to have a lower resolution, more softness and more grain, which would invalidate the results.

 

On the other hand, digital formats lend themselves perfectly to such a test, as they have standardized resolutions.  So, a Super16 full HD camera will have the same digital resolution as an 8"x10" full HD camera.

 

 

On 9/23/2020 at 9:09 AM, Jay60p said:

I did look at the SLR primes with the Turbo II speedbooster. It shrinks the first fringing seen, but it includes more of the edges of the

image circle, with more CA, so overall the fringing looked the same.

Yep.  Focal reducers tend to transfer the qualities of the larger format lens to the image of the smaller format.

 

 

On 9/23/2020 at 9:09 AM, Jay60p said:

Here is a review of my favorite Fuji lens that includes comments on the in-camera corrections (CA, vignetting, distortion) for anyone

unfamiliar with this: https://opticallimits.com/fuji_x/887-fuji1024f4ois?start=1

Thanks for the link!

 

For the benefit of those who are unfamiliar with in-camera corrections for chromatic aberration, vignetting, barrel/pincushion distortion, etc., such features have been implemented in digital cameras for a long time, and these corrections are not unique to Fuji cameras.

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On 9/23/2020 at 11:30 AM, noone said:

1) Equivalence theory HAS been tested and is accepted by the majority of photographers and scientists.

It is doubtful that any of the equivalency tests presented so would be accepted by "scientists" as a valid DOF/equivalency comparison.

 

 

On 9/23/2020 at 11:30 AM, noone said:

Most accept it even though no one has done an EXACT match (IE the photos LOOK very similar but someone will always point out a tiny difference) to the satisfaction of SOME but the deniers have never shown evidence that it is wrong either.

In regards to your claim in this thread that it is impossible to exactly match the focus between two lenses of the same focal length made for the same format from different manufacturers, I have already linked a comparison conducted by Shane Hurlbut in which the focus matches precisely -- much more exactly than any equivalency comparison presented here.

 

So, we probably can get a significantly closer match in a DOF equivalency test than what we have seen so far.

 

 

On 9/23/2020 at 11:30 AM, noone said:

The problem in getting an EXACT match is you would have to scale the equipment for an EXACT match and that would be near impossible.

This is false, as exemplified by the Shane Hurlbut test mentioned above.

 

On 9/23/2020 at 11:30 AM, noone said:

To the point the EASIEST way might be to build from scratch very simple low element number formulas that test this (but may not be great images).

That might work, especially if one likes to do things the hard way.  Not sure what the point is regarding low element numbers.

 

 

 

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1 hour ago, tupp said:

It is doubtful that any of the equivalency tests presented so would be accepted by "scientists" as a valid DOF/equivalency comparison.

 

 

In regards to your claim in this thread that it is impossible to exactly match the focus between two lenses of the same focal length made for the same format from different manufacturers, I have already linked a comparison conducted by Shane Hurlbut in which the focus matches precisely -- much more exactly than any equivalency comparison presented here.

 

So, we probably can get a significantly closer match in a DOF equivalency test than what we have seen so far.

 

 

This is false, as exemplified by the Shane Hurlbut test mentioned above.

 

That might work, especially if one likes to do things the hard way.  Not sure what the point is regarding low element numbers.

 

 

 

Sorry Tupp but I disagree and that is why there is no point discussing it with me.

Again, if anyone wants to ask about this, they are MUCH better off asking in a photography science/technology forum.

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This is as good a read on this as any.

https://www.spiedigitallibrary.org/journals/optical-engineering/volume-57/issue-11/110801/Equivalence-theory-for-cross-format-photographic-image-quality-comparisons/10.1117/1.OE.57.11.110801.full?SSO=1

"Nevertheless, real world IQ differences (including total image noise) will inevitably occur in practice even when equivalent photos are taken. These will arise due to differences in the underlying camera and lens technology, such as:

• sensor quantum efficiency;

• read noise;

• sensor pixel count;

• lens aberrations;

• JPEG tone curve; and

• image processing.

In other words, since the total light received by each format is the same when equivalent photos are taken, it is factors such as those above that explain real-world cross-format IQ differences rather than format size. These factors will be discussed further in Sec. 4."

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21 hours ago, noone said:

It's not a good read on this at all, as most of the information given is irrelevant.

 

Furthermore, many of the conclusions of this paper are dubious.

 

 

21 hours ago, noone said:

"Nevertheless, real world IQ differences (including total image noise) will inevitably occur in practice even when equivalent photos are taken. These will arise due to differences in the underlying camera and lens technology, such as:  • sensor quantum efficiency;

How is "sensor quantum efficiency" relevant to optical equivalency?

 

 

21 hours ago, noone said:

• read noise;

How is "read noise" relevant to optical equivalency?

 

 

21 hours ago, noone said:

• lens aberrations;

Lens aberrations are absolutely relevant to optical equivalency and DOF/focus.

 

According to Brian Caldwell, aberrations can affect DOF and lenses for larger formats generally have fewer aberrations.  Hence, the refractive optics of larger formats generally influence DOF differently than lenses for smaller formats.

 

Keep in mind that the DOF/equivalency formulas do not account for any effects of refractive optical elements, yet optical elements can affect DOF.

 

 

21 hours ago, noone said:

• JPEG tone curve; and

Again, this property is not really relevant to optical equivalency and DOF/focus.

 

 

21 hours ago, noone said:

• image processing.

This property is not really relevant to optical equivalency and DOF/focus.

 

 

21 hours ago, noone said:

In other words, since the total light received by each format is the same when equivalent photos are taken, it is factors such as those above that explain real-world cross-format IQ differences rather than format size. These factors will be discussed further in Sec. 4."

Only one of these six factors (aberrations) that you and the paper present are relevant to optical equivalency and DOF/focus.  So, why is this paper quotee/linked?

 

On the other hand, here is a choice sentence from he paper that immediately follows your excerpt:

Quote

Although real-world IQ differences could favor any of the cameras being compared when equivalent photos are taken, the advantage of a larger format is that it offers extra photographic capability over a smaller format.

 

There are other similar passages in that paper suggesting differences in image quality between different sized formats.

 

If the intention of quoting/linking that paper was to assert that it is difficult to get an exact match between two different lenses made by two different manufactures, I  once again direct you to Shane Hurlbut's test in which he compared two different lenses made by two very different manufacturers (Panasonic and Voigtlander), that exactly matched in regards to the softness/bokeh of the background, with only a slight difference in exposure/color.

 

So, a more exact match can be achieved than what we have seen so far in "equivalency tests."  In addition, we can compare the actual DOF, instead of seeing how closely one can match an arbitrarily soft background set at some arbitrary distance, while relying on lens aperture markings and inaccurate math entries.

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1 hour ago, tupp said:

It's not a good read on this at all, as most of the information given is irrelevant.

 

Furthermore, many of the conclusions of this paper are dubious.

 

 

How is "sensor quantum efficiency" relevant to optical equivalency?

 

 

How is "read noise" relevant to optical equivalency?

 

 

Lens aberrations are absolutely relevant to optical equivalency and DOF/focus.

 

According to Brian Caldwell, aberrations can affect DOF and lenses for larger formats generally have fewer aberrations.  Hence, the refractive optics of larger formats generally influence DOF differently than lenses for smaller formats.

 

Keep in mind that the DOF/equivalency formulas do not account for any effects of refractive optical elements, yet optical elements can affect DOF.

 

 

Again, this property is not really relevant to optical equivalency and DOF/focus.

 

 

This property is not really relevant to optical equivalency and DOF/focus.

 

 

Only one of these six factors (aberrations) that you and the paper present are relevant to optical equivalency and DOF/focus.  So, why is this paper quotee/linked?

 

On the other hand, here is a choice sentence from he paper that immediately follows your excerpt:

 

There are other similar passages in that paper suggesting differences in image quality between different sized formats.

 

If the intention of quoting/linking that paper was to assert that it is difficult to get an exact match between two different lenses made by two different manufactures, I  once again direct you to Shane Hurlbut's test in which he compared two different lenses made by two very different manufacturers (Panasonic and Voigtlander), that exactly matched in regards to the softness/bokeh of the background, with only a slight difference in exposure/color.

 

So, a more exact match can be achieved than what we have seen so far in "equivalency tests."  In addition, we can compare the actual DOF, instead of seeing how closely one can match an arbitrarily soft background set at some arbitrary distance, while relying on lens aperture markings and inaccurate math entries.

I Disagree!

Got ANY shred of evidence to support your case?

 

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7 hours ago, noone said:

I Disagree!

Well, I certainly appreciate your thoroughly addressing each one of my points and your giving a reasonable explanation of why you disagree.

 

 

7 hours ago, noone said:

Got ANY shred of evidence to support your case?

You mean, do I have any evidence other than all the photos, video links, and references that I have already provided in this thread, which you have largely avoided?

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8 hours ago, tupp said:

Well, I certainly appreciate your thoroughly addressing each one of my points and your giving a reasonable explanation of why you disagree.

 

 

You mean, do I have any evidence other than all the photos, video links, and references that I have already provided in this thread, which you have largely avoided?

Sigh!    I do not need to address each point as I disagree with YOUR (no one else its seems) theory that you have shown NO, zero, nil, zilch nix, NOTHING in evidence to support  other than saying there are (often tiny) difference so it MUST be because of the sensor size difference.

That article explains things pretty well to me and I can not understand how YOU can not understand that ANY difference in a system can explain very tiny differences in photos while at the same time you think those differences are explained by sensor size difference without a shred of evidence why ?

The fact that this amounts to many many pages of yes, no, yes, no is reason enough to end it now.

This thread should be locked.

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2 hours ago, noone said:

I do not need to address each point as I disagree with YOUR (no one else its seems) theory that you have shown

You certainly don't need to address each of my points, and, indeed, you have avoided almost all of them.

 

In regards to the your parenthetical insinuation, I would never claim that the number of individuals who agree/disagree with one's point has any bearing on the validity of that point.  However, please note how this poster unequivocally agrees with me on the problems inherent in your comparison test, saying, "I certainly can see what you're talking about in the areas you've highlighted. It's very clear."

 

 

2 hours ago, noone said:

NO, zero, nil, zilch nix, NOTHING in evidence to support  other than saying there are (often tiny) difference so it MUST be because of the sensor size difference.

In regards to my not providing evidence, again, are you referring to evidence other than all the photos, video links, and references that I have already provided in this thread, which you have yet to directly address?

 

Additionally, you have misconstrued (perhaps willfully) my point regarding sensor size.  I have continually maintained in this thread that it is the optics designed for a format size -- not the format size itself -- that produce general differences in format looks.

 

 

3 hours ago, noone said:

That article explains things pretty well to me and I can not understand how YOU can not understand that ANY difference in a system can explain very tiny differences in photos while at the same time you think those differences are explained by sensor size difference without a shred of evidence why ?

The paper that you linked does address points made in this thread, but a lot of the paper discusses properties which are irrelevant to DOF equivalency, as I pointed out in my previous post.  Interestingly, the paper frequently suggests that larger format optics have capabilities lacking in optics for smaller formats, which is what I and others have asserted.  Not sure how you missed those statements in the paper that you referenced.

 

Regardless, I have more than once linked Shane Hurlbut's example of an exact focus match between two different lenses made from two different manufacturers.  So, there should be no problem getting such a close DOF/focus match from other lenses with the proper methods.

 

Once again, I have repeatedly suggested that it is the sensor size itself that produces general differences in format looks -- it is the optics designed for a format size that produce general differences in format looks.  Somehow, you need to get that point through your head.

 

 

3 hours ago, noone said:

The fact that this amounts to many many pages of yes, no, yes, no is reason enough to end it now.  This thread should be locked.

Your thoughtful consideration and open-mindedness is admirable.

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58 minutes ago, tupp said:

Once again, I have repeatedly suggested that it is the sensor size itself that produces general differences in format looks

This should read:  "Once again, I have repeatedly suggested that it is NOT the sensor size itself that produces general differences in format looks..."

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59 minutes ago, tupp said:

This should read:  "Once again, I have repeatedly suggested that it is NOT the sensor size itself that produces general differences in format looks..."

Great so you DO you think the sensor size has nothing to do with any difference so we do agree!   

Of course if you do not agree with that, you would be able to prove it with science since you cannot prove it with photos (as any differences in photos taken with systems not identically scaled can be explained by difference in the systems.).

 

Now unless you CAN provide something (ANYTHING) showing how  (often tiny) differences in photos  could not even remotely be explained by differences in the equipment, I think we have gone several pages too far and I am out Really really really this time).

 

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1 hour ago, tupp said:

This should read:  "Once again, I have repeatedly suggested that it is NOT the sensor size itself that produces general differences in format looks..."

28 minutes ago, noone said:

Great so you DO you think the sensor size has nothing to do with any difference so we do agree!

The paragraph reads:  "I have repeatedly suggested that it is not the sensor size itself that produces general differences in format looks -- it is the optics designed for a format size that produce general differences in format looks."

 

Again, you somehow need to get that point through your head.

 

 

28 minutes ago, noone said:

Of course if you do not agree with that, you would be able to prove it with science since you cannot prove it with photos (as any differences in photos taken with systems not identically scaled can be explained by difference in the systems.).  Now unless you CAN provide something (ANYTHING) showing how  (often tiny) differences in photos  could not even remotely be explained by differences in the equipment, I think we have gone several pages too far and I am out Really really really this time).

Perhaps you should merely address my points individually and give a reasonable counter argument each one.  Unless, of course, you cannot give a reasonable counter argument. 

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  • 2 weeks later...
On 9/17/2020 at 12:27 PM, tupp said:

Using a speedbooster or focal reducer can allow the qualities of the larger format optics to be captured on a smaller format.

This hadn't occurred to me. I had to check this out.

So do my Full Frame Nikkor zooms show the shallower FF DOF on my Fuji X-T3 after mounting
on the Zhongyi Turbo II speed booster? I finally shot some tests and yes, they do.

So, no need to switch from APS-C or MFT to a new Full Frame camera to get the same shallower depth of field from your FF lenses, if you need it.

There are several good speed boosters (dumb or smart) that mount FF lenses with the added bonus of boosting light level by one stop, which you could use to reduce your ISO setting by half.

Myself, I use the speedbooster for the wider angle view rather than DOF. Simply stopping down one stop brings your DOF back to the deeper APS-C equivalent.

(As always my posts are for the newer users here like myself. I’ve used 35mm Kodachrome and
Bolex 16mm starting forty years ago, but I only started playing with a digital mirrorless recently.)

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