Testing a Sony A7sii for macro

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gardenersassistant
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Re: Testing a Sony A7sii for macro

Post by gardenersassistant »

rjlittlefield wrote:
Fri May 21, 2021 6:35 pm
gardenersassistant wrote:
Fri May 21, 2021 1:20 am
Direct comparison, Original to After AI Clear.
These are very impressive transformations!
Yes. I'm surprised at what is possible. Some years ago I concluded (from a single example, bad move) that f/128 was unusable and so I didn't go down that path. It is only recently, last summer, that out of desperation trying to get some half decent images of some very small (and hyperactive) flies that I tried tiny apertures again, even though I knew it wouldn't work. Well, it turned out I knew wrong. I got this image in particular, which was far better than anything I had achieved before, and off I went down this rabbit hole.

Image
1645 16 2020_06_01-05 1642 13 2020_06_02 DSC02305_PLab3 SP9LR 1300h-DNAIc-DNAI-PS-AISh by gardenersassistant, on Flickr

I think the big difference between that exercise and the earlier single-shot exercise was developments in post processing products coupled with a lot of post processing trial and error.
rjlittlefield wrote:
Fri May 21, 2021 6:35 pm
Interestingly, just today I was reading in one of my IEEE publications about some applications of "artificial intelligence". Quoting one snippet of the article:
DOI: 10.1109/MITP.2020.2985492 wrote:GANs can also be used to create superresolution imagery from low resolution inputs. Though the creation of high-resolution imagery from lower resolution input is not new, the technology can still struggle to remove noise and compression artifacts. GANs can optimize this process by creating a higher quality image than one that ever existed -- "fantasizing" details onto the low resolution image.
I doubt there's anything as powerful as a Generative Adversarial Network in your chain of tools.
I doubt it too. And really, I hope not. As far as I can tell it doesn't seem to invent new details, like for example I think Gigapixel AI does when resizing (and can sometimes make a real mess of of it). However, what I think my workflow does tend to do is to overcook (? terminology ->) edge contrasts on plant surfaces. An example of this, to my eye, is the in-focus area around the subject in the first example, which looks too "busy" to me.

Because of this effect I use a more moderate output sharpening approach for botanical subjects, for which I use more normal apertures anyway, and much lower magnification.

However, where the subject is an invertebrate, which needs stronger sharpening to look how I like it to look, there can be a conflict with what happens to the in-focus non-subject areas. When I originally processed that image I noticed the effect and would have done better to use some masking to tone down the non-subject in-focus areas (which can conveniently be done in DeNoise AI and, the main culprit I think, AI Clear). For whatever reason I didn't. And for this exercise it was not appropriate. I've been waiting for a while for someone to pick up on this effect, but so far no one has. People are too polite to mention it perhaps.
rjlittlefield wrote:
Fri May 21, 2021 6:35 pm
But I'm curious, have you ever shot the same subject using your highly post-processed single-shot workflow and using a high resolution stacked workflow, and studied them to see how the details compare?
No. I use focus stacking as one of my two main methods for botanical subjects, but I've not managed to get it to work to my satisfaction for invertebrates. There are practical issues, out in the field, which is where all my photography is done, and there is an aspect of invertebrate stacks for my type of (typically full body) framing that I don't much like - an unnaturally sudden transition between in-focus and out of focus areas of the background.

As to practicality, my subjects tend often to be in motion, or on foliage or a web that is moving in a breeze, or engaged in an activity that involves movement such as grooming, wrapping prey or blowing bubbles. I like shooting sequences of subject movement through the environment and subject activity, and with and without movement and activity I like to zoom in and out on the subject. And my subjects may turn up suddenly and disappear quickly.

All in all, focus stacking for invertebrates isn't a good fit for me and I've never put the effort into getting to grips with it. I don't know that I'm even capable of doing a good controlled environment comparison between tiny aperture single shot and focus stacked sweet spot aperture.

So, a single-shot approach is a better fit for me, hence my excursion into the land of tiny apertures to try to make the best I can (as someone who prefers to have a lot of the subject in focus) of a single-shot approach.
rjlittlefield wrote:
Fri May 21, 2021 6:35 pm

I'm not surprised that people are surprised. I am also not surprised that they can't tell the difference, since that is exactly what properly applied theory predicts.
Exactly so. With another factor thrown in. All my invertebrate images, and so all of the images I use in these exercises, use small (in this case around effective f/45 full frame equivalent) apertures, and dominant diffraction is a great leveller. That said, I have got similarly (almost) indistinguishable results as between MFT and full frame using ordinary apertures for botanical comparisons which were as nearly like for like as I could make them and which I examined rather carefully. (I'll look up links to the two write-ups for that exercise if anyone is interested.)

--Rik
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joshmacro
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Re: Testing a Sony A7sii for macro

Post by joshmacro »

rjlittlefield wrote: ↑Fri May 21, 2021 8:35 pm
But I'm curious, have you ever shot the same subject using your highly post-processed single-shot workflow and using a high resolution stacked workflow, and studied them to see how the details compare?
gardenersassistant wrote:
Sat May 22, 2021 2:50 am
No. I use focus stacking as one of my two main methods for botanical subjects, but I've not managed to get it to work to my satisfaction for invertebrates. There are practical issues, out in the field, which is where all my photography is done, and there is an aspect of invertebrate stacks for my type of (typically full body) framing that I don't much like - an unnaturally sudden transition between in-focus and out of focus areas of the background.
Can you do a comparison in studio? Doesn't have to be an invertebrate subject. It would help seeing the difference in a real example.

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Re: Testing a Sony A7sii for macro

Post by rjlittlefield »

gardenersassistant wrote:
Sat May 22, 2021 2:50 am
Yes. I'm surprised at what is possible. Some years ago I concluded (from a single example, bad move) that f/128 was unusable and so I didn't go down that path.
Running some quick calculations...

Using the MTF diffraction equations at viewtopic.php?p=124831#124831 , with the usual lambda = 550nm (green light), f/128 gives a cutoff frequency nu_0 = 14.2 cycles/mm. For full frame, with sensor width 36 mm, that gives 511 cycles per frame width. At the Nyquist limit of 2 samples per cycle, the minimum number of pixels is 1022 wide. That's the value that Nikon would quote for a sensor pitch that is "optimally" matched to the optics. But their definition of "optimal" does not give a uniform representation of details above about half the cutoff frequency, for the reasons discussed at viewtopic.php?f=8&t=41213 (and earlier, at viewtopic.php?t=2439). To get a good robust representation all the way out to cutoff, you need more like 3-4 samples per cycle, which suggests more like 1500-2000 pixels width given your workflow that restores details that are severely softened by diffraction, but not totally lost.

So yep, with aggressive but well controlled post-processing, it's now possible to stop down much farther than we previously accepted as a practical limit.

--Rik

gardenersassistant
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Comparing a focus stack and a tiny aperture capture

Post by gardenersassistant »

joshmacro wrote:
Sat May 22, 2021 6:17 am
rjlittlefield wrote: ↑Fri May 21, 2021 8:35 pm
But I'm curious, have you ever shot the same subject using your highly post-processed single-shot workflow and using a high resolution stacked workflow, and studied them to see how the details compare?
gardenersassistant wrote:
Sat May 22, 2021 2:50 am
No. I use focus stacking as one of my two main methods for botanical subjects, but I've not managed to get it to work to my satisfaction for invertebrates. There are practical issues, out in the field, which is where all my photography is done, and there is an aspect of invertebrate stacks for my type of (typically full body) framing that I don't much like - an unnaturally sudden transition between in-focus and out of focus areas of the background.
Can you do a comparison in studio? Doesn't have to be an invertebrate subject. It would help seeing the difference in a real example.
Well, I've had a go. But there are loads of caveats. First I'll describe what I did.

Procedure

I looked around all the window sills and under one of them I found a dead woodlouse. It had synthetic strands from a carpet tangled up on it.

I set up the equipment like this:

Image
1896 Illustration 1 by gardenersassistant, on Flickr

Image
1896 Illustration 2 by gardenersassistant, on Flickr

And then:
  • Shooting raw, with magnification at around 3.5:1, I captured single shots at f/45 and f/64. I then captured 33 shots for focus stacking.
  • I used DXO PhotoLab with my usual starter preset on all the images to produce TIFF files.
  • I used Helicon Focus to do a Depth Map stack and a Pyramid stack and output the stacked images as TIFF files. I did not do any retouching.
  • I imported the two stack TIFF files and the two tiny aperture TIFF files into Lightroom and ran AutoTone on them. I ran a minor preset on the two single shots (part of my normal procedure for tiny aperture images). I adjusted the Blacks, Whites and Exposure sliders for each image to try to get them looking fairly similar in terms of lightness. I exported from Lightroom as 1300 pixel high TIFF.
  • To each of the four 1300 pixel high TIFF files I applied Topaz DeNoise AI, exporting to TIFF, and then applied Topaz AI Clear to the TIFF files and exported to 1300 pixel high JPEG.
Caveats

I have a fair amount of experience with stacking, but of a very different type: close-ups of botanical subjects, stacked from hand-held 6K videos captured in the field, including in breezy conditions. I have almost no experience with focus stacking for invertebrates and so someone else can probably do a much better job with this exercise's stacks.

I'm not equipped to do stacking for small subjects. The camera I'm using doesn't do focus bracketing, but even if it did that wouldn't help, because the Lens I'm using is a manual focus lens. So I had to do the image capture by hand. I turned the wheel on the (cheap and basic) focus slider in as small increments as I could, but I don't think they were small enough. Also there was a lot of give in the tripod etc setup, so the captures were not as nicely spaced as they would be on a mechanised setup.

There were many issues to do with the processing. We can discuss them if you like, but it doesn't feel like that would be productive to me. I did what I felt was reasonable and practical.

The images are only 1300 pixels high. That is because that is the size I do my outputs and there is no point in producing anything much larger from a tiny aperture capture. So for a like for like comparison the focus stacked images had to be downsized.

I have posted the images at 1024 pixels on the long side, as I think may be required for this site. The 1300 pixel high versions are in this album at Flickr. I can make the raw files available if anyone wants to play with them.

The images

Depth map stack

Image
1896 1 Depth map DSC01472_PLab4 33 B,Radius30,Smoothing4 LR 1300h DNAI DNAIc by gardenersassistant, on Flickr

Pyramid stack

Image
1896 2 Pyramid DSC01472_PLab4 33 C,Smoothing4 LR 1300h DNAI DNAIc by gardenersassistant, on Flickr

Single image, f/64 (This is the f-number reported by the camera; it takes account of the teleconverters. The lens f-number would have been f/22, minimum aperture. The effective f-number would have been around f/140.)

Image1896 3 Single shot F64 DSC01415_PLab4 LR 1300h DNAI DNAIc by gardenersassistant, on Flickr

Single image, f/45 (This is the f-number I have mostly been using for my tiny aperture images. The lens f-number would have been f/16. The effective f-number would have been around f/100.)

Image
1896 4 Single shot F45 DSC01416_PLab4 LR 1300h DNAI DNAIc by gardenersassistant, on Flickr

Conclusions

Focus stacking can produce images which are much larger and more detailed, have greater depth of field and less noise than images produced using tiny apertures.

Focus stacking can only be used for subjects which are pretty much stationary. Tiny aperture captures can be used for subjects that are in motion, on foliage etc that is moving (a lot) in a breeze or engaging in activities involving movement such as grooming, wrapping prey or blowing bubbles.

Focus stacking captures can be slow and/or difficult to execute for invertebrates and it can be time-consuming to correct/hide flaws in focus stacks. Tiny aperture image capture can be executed at a sustained rate of one every 1 to 2 seconds for long periods. It can be fairly straightforward and quick to process relatively large numbers of tiny aperture images.
Nick

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Rework and reposts of my images posted in this forum are always welcome, especially if they come with an explanation of what you did and how you did it.

gardenersassistant
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Re: Testing a Sony A7sii for macro

Post by gardenersassistant »

rjlittlefield wrote:
Sat May 22, 2021 9:52 am
Running some quick calculations...

Using the MTF diffraction equations at viewtopic.php?p=124831#124831 , with the usual lambda = 550nm (green light), f/128 gives a cutoff frequency nu_0 = 14.2 cycles/mm. For full frame, with sensor width 36 mm, that gives 511 cycles per frame width. At the Nyquist limit of 2 samples per cycle, the minimum number of pixels is 1022 wide. That's the value that Nikon would quote for a sensor pitch that is "optimally" matched to the optics. But their definition of "optimal" does not give a uniform representation of details above about half the cutoff frequency, for the reasons discussed at viewtopic.php?f=8&t=41213 (and earlier, at viewtopic.php?t=2439).
I found the second and third linked posts very interesting and informative. Thank you. The first one was beyond me.
Nick

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Rework and reposts of my images posted in this forum are always welcome, especially if they come with an explanation of what you did and how you did it.

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Re: Comparing a focus stack and a tiny aperture capture

Post by rjlittlefield »

gardenersassistant wrote:
Sat May 22, 2021 2:57 pm
Conclusions

Focus stacking can produce images which are much larger and more detailed, have greater depth of field and less noise than images produced using tiny apertures.

Focus stacking can only be used for subjects which are pretty much stationary. Tiny aperture captures can be used for subjects that are in motion, on foliage etc that is moving (a lot) in a breeze or engaging in activities involving movement such as grooming, wrapping prey or blowing bubbles.

Focus stacking captures can be slow and/or difficult to execute for invertebrates and it can be time-consuming to correct/hide flaws in focus stacks. Tiny aperture image capture can be executed at a sustained rate of one every 1 to 2 seconds for long periods. It can be fairly straightforward and quick to process relatively large numbers of tiny aperture images.
That all sounds fair to me. It's very much a "horses for courses" situation.

For whatever it's worth, I downloaded the Flickr versions and laid up a flash-to-compare type animation.

What we're seeing here is 400% blowup of the single-shot "f/45", alternating with the pyramid stack. I rescaled the stack so as to get almost perfect alignment between the two images, so as to make the flash-to-compare easier to absorb.
400pct_flash_to_compare.gif
This area shows mostly part of the spiderweb that covers the head of the woodlouse.

I didn't label the outputs because I think there'll be no trouble telling them apart: the one with more fine detail but an obvious band of blur is the stacked output.

What I'm particularly interested in is the treatment of fine details in the spiderweb. The f/45+sharpening image mostly preserves the major arrangements of the fibers that are already present, but a lot of the fine fibers are totally lost and in some places new coarse structure seems to have been generated by some sort of aggregation of fine fibers. This is especially prominent in the areas above the brown blob and in the upper left corner, where the spiderweb was captured in sharp focus in the stack.

Effects that look sort of the same but sort of different appear in other areas with different fine structure, for example on this leg:
400pct_flash_to_compare_2.gif

I don't see that any of this impacts Nick's use of this technology for his purposes. Small aperture one shot is the only technique I know for capturing high DOF images of small active critters. But it does seem clear that this image has reached beyond the limit of accurately capturing fine detail, even at the 1300 pixels size.

--Rik

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Re: Testing a Sony A7sii for macro

Post by rjlittlefield »

gardenersassistant wrote:
Sat May 22, 2021 3:06 pm
rjlittlefield wrote:
Sat May 22, 2021 9:52 am
Running some quick calculations...

Using the MTF diffraction equations at viewtopic.php?p=124831#124831 , with the usual lambda = 550nm (green light), f/128 gives a cutoff frequency nu_0 = 14.2 cycles/mm. For full frame, with sensor width 36 mm, that gives 511 cycles per frame width. At the Nyquist limit of 2 samples per cycle, the minimum number of pixels is 1022 wide. That's the value that Nikon would quote for a sensor pitch that is "optimally" matched to the optics. But their definition of "optimal" does not give a uniform representation of details above about half the cutoff frequency, for the reasons discussed at viewtopic.php?f=8&t=41213 (and earlier, at viewtopic.php?t=2439).
I found the second and third linked posts very interesting and informative. Thank you. The first one was beyond me.
Thanks for the feedback. The first one is a reference post, provided so that somebody who wants to check my calculations can follow along. It's what I'd call "concise but cryptic", usable only after studying a bunch of other stuff to learn the concepts. The other two are more conversational, intended to help some learning.

--Rik

joshmacro
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Re: Testing a Sony A7sii for macro

Post by joshmacro »

Thank you Nick for conducting a test. Quite interesting to have a real world comparison. Rik's flash is helpful. Although just by looking at the Flickr images tells the story - the focus stacked images have far and away better quality. However, I do understand how the small aperture technique is a valuable tool for your subjects.

gardenersassistant
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Re: Comparing a focus stack and a tiny aperture capture

Post by gardenersassistant »

rjlittlefield wrote:
Sat May 22, 2021 5:07 pm
gardenersassistant wrote:
Sat May 22, 2021 2:57 pm
Conclusions

Focus stacking can produce images which are much larger and more detailed, have greater depth of field and less noise than images produced using tiny apertures.

Focus stacking can only be used for subjects which are pretty much stationary. Tiny aperture captures can be used for subjects that are in motion, on foliage etc that is moving (a lot) in a breeze or engaging in activities involving movement such as grooming, wrapping prey or blowing bubbles.

Focus stacking captures can be slow and/or difficult to execute for invertebrates and it can be time-consuming to correct/hide flaws in focus stacks. Tiny aperture image capture can be executed at a sustained rate of one every 1 to 2 seconds for long periods. It can be fairly straightforward and quick to process relatively large numbers of tiny aperture images.
That all sounds fair to me. It's very much a "horses for courses" situation.

For whatever it's worth, I downloaded the Flickr versions and laid up a flash-to-compare type animation.

What we're seeing here is 400% blowup of the single-shot "f/45", alternating with the pyramid stack. I rescaled the stack so as to get almost perfect alignment between the two images, so as to make the flash-to-compare easier to absorb.

400pct_flash_to_compare.gif

This area shows mostly part of the spiderweb that covers the head of the woodlouse.

I didn't label the outputs because I think there'll be no trouble telling them apart: the one with more fine detail but an obvious band of blur is the stacked output.

What I'm particularly interested in is the treatment of fine details in the spiderweb. The f/45+sharpening image mostly preserves the major arrangements of the fibers that are already present, but a lot of the fine fibers are totally lost and in some places new coarse structure seems to have been generated by some sort of aggregation of fine fibers. This is especially prominent in the areas above the brown blob and in the upper left corner, where the spiderweb was captured in sharp focus in the stack.

Effects that look sort of the same but sort of different appear in other areas with different fine structure, for example on this leg:
400pct_flash_to_compare_2.gif


I don't see that any of this impacts Nick's use of this technology for his purposes. Small aperture one shot is the only technique I know for capturing high DOF images of small active critters. But it does seem clear that this image has reached beyond the limit of accurately capturing fine detail, even at the 1300 pixels size.

--Rik
That is hugely informative Rik (and copied into my archive!). Thanks so much for doing this very careful piece of work and illustrating and describing the results so clearly. And a very clear conclusion, "this image has reached beyond the limit of accurately capturing fine detail, even at the 1300 pixels size" and I'm sure that will be true of others too. I must now include that as one of the caveats when describing this technique. It seems that I am hovering around the edge of the acceptable, at least given my current processing products and methods and my personal criteria for acceptability. I did a session at f/57 a couple of days ago. I am not going to use any of them.
Nick

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Re: Testing a Sony A7sii for macro

Post by gardenersassistant »

rjlittlefield wrote:
Sat May 22, 2021 5:19 pm
gardenersassistant wrote:
Sat May 22, 2021 3:06 pm
rjlittlefield wrote:
Sat May 22, 2021 9:52 am
Running some quick calculations...

Using the MTF diffraction equations at viewtopic.php?p=124831#124831 , with the usual lambda = 550nm (green light), f/128 gives a cutoff frequency nu_0 = 14.2 cycles/mm. For full frame, with sensor width 36 mm, that gives 511 cycles per frame width. At the Nyquist limit of 2 samples per cycle, the minimum number of pixels is 1022 wide. That's the value that Nikon would quote for a sensor pitch that is "optimally" matched to the optics. But their definition of "optimal" does not give a uniform representation of details above about half the cutoff frequency, for the reasons discussed at viewtopic.php?f=8&t=41213 (and earlier, at viewtopic.php?t=2439).
I found the second and third linked posts very interesting and informative. Thank you. The first one was beyond me.
Thanks for the feedback. The first one is a reference post, provided so that somebody who wants to check my calculations can follow along. It's what I'd call "concise but cryptic", usable only after studying a bunch of other stuff to learn the concepts.
I'm glad it wasn't just me being dense. :)
rjlittlefield wrote:
Sat May 22, 2021 5:19 pm
The other two are more conversational, intended to help some learning.
Worked as intended for me.
Nick

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Rework and reposts of my images posted in this forum are always welcome, especially if they come with an explanation of what you did and how you did it.

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Re: Testing a Sony A7sii for macro

Post by gardenersassistant »

joshmacro wrote:
Sat May 22, 2021 5:21 pm
Thank you Nick for conducting a test. Quite interesting to have a real world comparison. Rik's flash is helpful. Although just by looking at the Flickr images tells the story - the focus stacked images have far and away better quality. However, I do understand how the small aperture technique is a valuable tool for your subjects.
Thanks. Yes, definitely horses for courses. (I do actually use focus stacking, for botanical subjects, but not for reasons of capturing great detail that allows zoomed in close examination, but for aesthetic reasons.)
Nick

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Scarodactyl
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Re: Testing a Sony A7sii for macro

Post by Scarodactyl »

This has been a fascinating thread. I think we all knew that typical high res stacking is overkill for web resolutions but I'm amazed how far you can push this and still get really nice looking results.

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Re: Testing a Sony A7sii for macro

Post by gardenersassistant »

Scarodactyl wrote:
Sun May 23, 2021 10:29 am
This has been a fascinating thread. I think we all knew that typical high res stacking is overkill for web resolutions but I'm amazed how far you can push this and still get really nice looking results.
I think perhaps this depends on what one thinks of as typical by way of focus stacks. I think you can get a lot of mileage out of single shots, and they are the only way to get action/activity sequences, but I don't think high resolution stacking is necessarily overkill for web resolutions. It's true that I do see stacks that I think didn't need stacking, or where the stacks have off-putting artefacts , but there again I see stacks of insect's and spiders' heads for example that look wonderful at web resolutions and could only be done with stacking. And sometimes they are posted large and you can zoom in and see even more detail (although that can be a bit double-edged as a stack that looks good at web resolution may show imperfections that for me at least rather spoil the effect if I get to look closer at it).

I use stacking for web resolution flowers, berries, seed pods etc. That is because I can get a look that I often can't get with single stills. I generally use both stills and focus stacks for every subject, the stills done with aperture bracketing and the stacks done via 6K video captures. During selection/processing I can then choose whether one of the stills or a focus stack gives me the balance I best like between the focus coverage of the subject and the rendition of the background.
Nick

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Rework and reposts of my images posted in this forum are always welcome, especially if they come with an explanation of what you did and how you did it.

Dalantech
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Re: Testing a Sony A7sii for macro

Post by Dalantech »

rjlittlefield wrote:
Fri May 21, 2021 9:37 pm

I'm curious where you've seen such efforts. Around PMN, my impression is that physics-defying claims don't last very long before being squashed. But maybe I'm wrong about that. Can you point to some claims that defy physics?

--Rik
There are numerous people claiming that smaller than full frame sensors provide more depth of field, ignoring the simple fact that it's easier to fill the frame at lower magnifications with them and it's that lower mag the accounts for the increase in depth.

With the rest you and I are gonna have to agree to disagree. Your analogy of the four burner stove is pretty illogical, IMHO...

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Re: Testing a Sony A7sii for macro

Post by rjlittlefield »

Dalantech wrote:
Sun May 23, 2021 1:06 pm
There are numerous people claiming that smaller than full frame sensors provide more depth of field, ignoring the simple fact that it's easier to fill the frame at lower magnifications with them and it's that lower mag the accounts for the increase in depth.
Please read my words here very carefully. Do not skip ahead because you think I'm disagreeing with you. I'm not.

First, it is absolutely critical to keep in mind what is being held constant.

Smaller sensors give more depth of field IF you shoot the same size subject at the same F-number.

But in that case they also give more noise and more diffraction blur in the final image.

The resulting image from small sensor is exactly the same as from a larger sensor stopped down farther, varying effective F-number in direct proportion to the sensor size.

That is, f/8 on Micro Four-Thirds will give more DOF but also more noise and diffraction blur than f/8 on full frame, and exactly the same as f/16 on full frame.

In other words, there is no real advantage to smaller sensors regarding DOF. But if people don't keep straight what's being held constant, it can look like there is.

The main source of conflict that I see comes from people not being clear about what's being held constant.

Earlier, I linked to a thread about equivalent images analysis. The thread is titled "Sensor size: how does it matter?" It was written 13 years ago, and no errors have been found in it since then.

You might find it helpful to thoroughly study and absorb what I've written there.

As far as I can tell, the point that you're trying to make is exactly what the analysis in the thread shows.

--Rik

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