Large format macro tests

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Lou Jost
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Re: Large format macro tests

Post by Lou Jost »

We differ on what we mean by "image quality". I am discussing the quality of the aerial image that the sensor is trying to capture. For that, obviously, "sharp at 100% resolution" is not an adequate criterion, because you could easily ahieve that with any reasonable lens if you used a low-megapixel sensor. A quality image in my sense is one which resolves lots of subject detail. Higher quality means more subject detail (all else being equal, like color aberrations and distortion).

I think you also implicitly use this definition. You have pushed the envelope and spent a fortune perfecting sensor shifting of super-high resolution lenses. You are way ahead of me on this. As you know, I got some of my best lenses from you. So I think deep down you have the same urge and a similar criterion.

By the way, my intended use is mainly for permanently documenting the microstructures of my new species of plants. I am often the only person who sees them alive, and few of my fellow scientists will even be able to see the preserved alcohol samples in the Ecuadorian herbaria. They can be shared digitally, though.

ray_parkhurst
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Re: Large format macro tests

Post by ray_parkhurst »

Lou Jost wrote:
Wed Sep 02, 2020 3:16 pm
We differ on what we mean by "image quality". I am discussing the quality of the aerial image that the sensor is trying to capture. For that, obviously, "sharp at 100% resolution" is not an adequate criterion, because you could easily ahieve that with any reasonable lens if you used a low-megapixel sensor. A quality image in my sense is one which resolves lots of subject detail. Higher quality means more subject detail (all else being equal, like color aberrations and distortion).

I think you also implicitly use this definition. You have pushed the envelope and spent a fortune perfecting sensor shifting of super-high resolution lenses. You are way ahead of me on this. As you know, I got some of my best lenses from you. So I think deep down you have the same urge and a similar criterion.

By the way, my intended use is mainly for permanently documenting the microstructures of my new species of plants. I am often the only person who sees them alive, and few of my fellow scientists will even be able to see the preserved alcohol samples in the Ecuadorian herbaria. They can be shared digitally, though.
For sure I have tried pushing the envelope to capture as much image detail as possible, but with the same end goal...to get the best 100% pixel-level detail.

Perhaps the concept of "100%" is what is elusive here. Can we agree that viewing a digital image at greater than 100% doesn't add anything to the image vs 100%, and in fact the IQ may be degraded unless you increase your viewing distance? I suppose this statement is not fully correct though, since if the monitor pixels are very small, or you are far away from the monitor, then you may be able to see more information and detail at higher than 100%. But let's say you have arranged your viewing distance such that you can indeed see all details of a perfect 100% image on your monitor, then the IQ won't improve at higher monitor magnification and may be degraded.

I think we can agree that viewing at lower than 100% reduces the available information. This may not be a bad thing, if the information is limited/partial (such as with Bayer) or the 100% image has distracting artifacts (such as false colors or questionable details), but in general reducing information is not a good thing.

So if viewing at higher OR lower than 100% causes IQ degradation and/or information loss, isn't creating the best possible 100% image the correct goal?

Regarding the microstructure documentation of new species, all I can say is that's really cool. Obviously this deserves the best equipment and techniques to gather the most information possible, and your images have a very different purpose and audience than mine do.

Lou Jost
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Re: Large format macro tests

Post by Lou Jost »

For sure I have tried pushing the envelope to capture as much image detail as possible, but with the same end goal...to get the best 100% pixel-level detail.
I think you are leaving out something important about your goal. If that was really your goal, you would have stopped with a low-megapixel sensor and any reasonable lens. That would create a super-sharp image at 100%. There is something more you are after, that you are not verbalizing.

My goal is to make images that, for a given FOV, capture as much information as possible. I don't want the lens to outresolve the sensor. That results in lost information and that is bad, as you said. This REQUIRES that the image not look good at 100%. If it looked good at 100%, that's a sign that the lens is outresolving the sensor, so increasing the sensor resolution will give you more detail.

ray_parkhurst
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Re: Large format macro tests

Post by ray_parkhurst »

Lou Jost wrote:
Wed Sep 02, 2020 5:01 pm

My goal is to make images that, for a given FOV, capture as much information as possible. I don't want the lens to outresolve the sensor. That results in lost information and that is bad, as you said. This REQUIRES that the image not look good at 100%. If it looked good at 100%, that's a sign that the lens is outresolving the sensor, so increasing the sensor resolution will give you more detail.
So, what amount of downsizing do you view at? Let's say you create a 6-tile image, each tile 180MP, such that the tiled composite is ~1GP. How do you view this image? Since it looks bad at 100%, I assume you would not view it like that. Even at 20% it's a 7.2MP image, much larger than can be viewed on a computer screen, and most of that precious information is lost. Do you only print your images? How big do you print so that all that 180MP of information is presented?

I'm thinking that maybe your goal of capturing such high-information images is more for archival / academic purposes rather than practical.

Lou Jost
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Re: Large format macro tests

Post by Lou Jost »

I want to archive them digitally, though I also dream of someday making big exhibition prints. Exhibitions often have prints more than a meter wide, and allow a close approach to examine details. One of my friends made prints almost 2 meters high for an exhibition that I introduced in Amsterdam. They were done on Hasselblad medium format cameras, and they looked great, but they could have been sharper.

ray_parkhurst
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Re: Large format macro tests

Post by ray_parkhurst »

Lou Jost wrote:
Wed Sep 02, 2020 5:58 pm
I want to archive them digitally, though I also dream of someday making big exhibition prints. Exhibitions often have prints more than a meter wide, and allow a close approach to examine details. One of my friends made prints almost 2 meters high for an exhibition that I introduced in Amsterdam. They were done on Hasselblad medium format cameras, and they looked great, but they could have been sharper.
OK, makes sense. Big prints are a completely different end product than I am pursuing. Hopefully you can see the difference, and why my goal of best 100% digital viewing quality makes sense for my application. It may be that to get best 100% detail at a practical and effective image size I will need to go to similar lengths to create images worthy of big prints, then downsize them to the appropriate size for elimination of artifacts and practical viewing. I'm not sure yet how far I can go with the 95PN, or the RF3p5x, or how pixel shifting will help. It's a work in progress.

Lou Jost
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Re: Large format macro tests

Post by Lou Jost »

I think high resolution is an important quality in nature photography. I want people to forget that they are looking at an image; I want them to be able to run their eyes over the textures and details that are an essential part of an organism's beauty, as if they were examining the thing itself.

In the 1980s I went to extremes to get the highest possible resolution in my bird photos. I used the best lens I could afford, and I made perfect lighting using an array of flashes all set to 1/128 power, to absolutely stop any motion, and with these arrays arrabged in tripods around my chosen branch I could use Kodachrome 25 film for high resolution. I used tape recordings and stuffed birds to make the target bird land on the particular branch next to the flashes, after getting to know the individual birds over the course of weeks or months. Those pictures made it onto the covers and spreads of magazines (even Sports Illustrated), partly because of their resolution. A high-end printing company chose one of those images to make into a big poster demonstrating and promoting their work. That was entirely due to the high resolution of the image.

In the 1990s I sometimes carried a view camera through tropical forests for macro photography. It was nearly impossible but I did get one or two good pictures, and their effect depends entirely on the high resolution and beautiful tonalities of 4x5 film.

So even without giant prints, and even without scientific or academic significance, I have always felt that high resolution is worth pursuing. I really miss 4x5 film.

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Re: Large format macro tests

Post by rjlittlefield »

ray_parkhurst wrote:
Wed Sep 02, 2020 6:24 pm
Hopefully you can see ... why my goal of best 100% digital viewing quality makes sense for my application.
I still don't feel confident that I clearly understand what your application is.

The best summary I can write, at this moment, is that you want to present as much detail as possible, to an audience that will judge you harshly if the image does not look sharp at 100%.

Is that correct? If not, then what have I missed?

--Rik

Lou Jost
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Re: Large format macro tests

Post by Lou Jost »

There has to be something else in your criterion, Ray. You can always get 100% sharpness from an image if you downsample it enough. But that's losing information, and you agreed that is bad. You must have some additional constraint that you are following. Maybe "100% sharpness on a high-end consumer camera sensor" or something like that?

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Re: Large format macro tests

Post by ray_parkhurst »

rjlittlefield wrote:
Wed Sep 02, 2020 8:46 pm
ray_parkhurst wrote:
Wed Sep 02, 2020 6:24 pm
Hopefully you can see ... why my goal of best 100% digital viewing quality makes sense for my application.
I still don't feel confident that I clearly understand what your application is.

The best summary I can write, at this moment, is that you want to present as much detail as possible, to an audience that will judge you harshly if the image does not look sharp at 100%.

Is that correct? If not, then what have I missed?

--Rik
I have no idea if anyone will "judge me harshly" Rik, and I don't really care one way or the other as I'm not really motivated by trying to please others. As I've stated many times before, it has been my goal for many years to be able to present a single image of coins (generally Lincoln Wheat Cents) with enough resolution and sharpness that every die marker can be seen clearly. The general method today of doing that is by taking about a dozen afocal microscope images of the specific variety markers and other die markers unique to the variety. This often results in many missed markers that can be relevant to identifying the variety. By capturing enough detail, and presenting it with enough sharpness, a single image can replace those dozen afocal images, and same time give a detailed view of much more of the coin surface than those dozen images cover. My audience is a group of coin collectors who would use the images to identify if a coin they have found is from the same die and die state as the one pictured. Often folks will image their own coin and use snapshots of my image to do an overlay to prove they were struck from the same die. Sometimes the details are large and obvious, but often they are very small and difficult to see clearly, and thus the highest quality images help in attribution of a found coin.

Generally I've been hosting these images on EasyZoom, though I'm looking at other alternatives as well. BTW if anyone knows of a good alternative for large image hosting, please let me know. With EasyZoom, you can see the whole coin, or zoom-in on the details in several steps, with each step loading more detail to the image. The final step is at 100%. They do now offer a "max" button where a higher zoom (not sure the %) is presented, but no more detail can be had from the image.

Hopefully this explains the application but do let me know if anything is unclear.

edited to add: Lou, your reply came in while I was writing my reply to Rik. Does the above help in understanding, or is the 100% IQ requirement still unclear?

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Re: Large format macro tests

Post by rjlittlefield »

ray_parkhurst wrote:
Wed Sep 02, 2020 9:12 pm
Hopefully this explains the application but do let me know if anything is unclear.
OK, let's suppose for a moment that I understand the application.

Then here's the conflict.

If I were to do that application, my 100% view would not look sharp. This is because a digital image that looks sharp at 100% must necessarily lose information that was present in the optical image it represents. Discussion at http://www.photomacrography.net/forum/v ... php?t=2439 and many other places.

But as I understand it, you want your 100% view to look sharp. That's the part I don't understand.

What part of your application requires that the image looks sharp at 100% ?

Or is it OK with you if the image does not look sharp at 100%, as long as it does not contain any misleading artifacts?

--Rik

Lou Jost
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Re: Large format macro tests

Post by Lou Jost »

with enough resolution and sharpness that every die marker can be seen clearly
Lou, your reply came in while I was writing my reply to Rik. Does the above help in understanding, or is the 100% IQ requirement still unclear?
THis is the part you've been leaving out. Your main criterion is NOT just that the image should be sharp at 100%. You have this additional criterion that you want enough resolution to see certain marks on the coin. With that addition, things make sense. Without that addition it did not make sense.

ray_parkhurst
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Re: Large format macro tests

Post by ray_parkhurst »

rjlittlefield wrote:
Wed Sep 02, 2020 9:48 pm
ray_parkhurst wrote:
Wed Sep 02, 2020 9:12 pm
Hopefully this explains the application but do let me know if anything is unclear.
OK, let's suppose for a moment that I understand the application.

Then here's the conflict.

If I were to do that application, my 100% view would not look sharp. This is because a digital image that looks sharp at 100% must necessarily lose information that was present in the optical image it represents. Discussion at http://www.photomacrography.net/forum/v ... php?t=2439 and many other places.

But as I understand it, you want your 100% view to look sharp. That's the part I don't understand.

What part of your application requires that the image looks sharp at 100% ?

Or is it OK with you if the image does not look sharp at 100%, as long as it does not contain any misleading artifacts?

--Rik
Similar to other scientific endeavors, the traditional way die variety details have been presented for attribution purposes is through line drawings made by viewing the coin through a microscope. The relevant details are not extremely small, and indeed a practical maximum magnification is ~10x. This makes it possible for folks with hand loupes to view their coins and compare what they see to the drawings for attribution of the particular variety. Attribution has been done this way for over 100 years. Some of the best attribution guides include other die markers that help with the attribution. The images I want to create take the place of these attribution guide drawings, so what I need is a sharp, clear image that shows the relevant details needed for attribution. Showing smaller details can actually be detrimental as they can distract from the more relevant ones.

Early photographic attribution guides were done in black and white. Even after color photography became common, most guides were still done in black and white. This eliminates confusion due to the variations in color, and conforms to the historical guides. Indeed I've come close to purchasing a monochrome camera for use in this application. That would give an immediate and significant boost in detail resolution.

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Re: Large format macro tests

Post by rjlittlefield »

Got it, thanks.

So now I'm curious, why have you not bought the monochrome camera? It seems like that would both increase sharpness and eliminate the Bayer artifacts that have plagued you.

--Rik

ray_parkhurst
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Re: Large format macro tests

Post by ray_parkhurst »

rjlittlefield wrote:
Thu Sep 03, 2020 8:57 am
Got it, thanks.

So now I'm curious, why have you not bought the monochrome camera? It seems like that would both increase sharpness and eliminate the Bayer artifacts that have plagued you.

--Rik
Yes, I knew that would be your next question. As the old adage goes, you don't know a subject until you teach it to others. The post above was the first time I've ever explained to anyone the historical context of the photos I'm making. The monochrome concept has been lurking back of mind for years, but I've been loathe to give up on color as it is so important for the Cents that I photograph. I've never thought seriously about separating the general full-coin photography I do versus the attribution detail photography. Writing this out has focused my thoughts a bit better, and perhaps a monochrome camera is indeed my best way forward. It jibes well with the probable need to have a second setup (much taller for the long FL / high mag lenses) as well.

I will look into current monochrome options.

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