Author Topic: Optical constraints for DSLRs > 36mp  (Read 8163 times)

Birna Rørslett

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Re: Optical constraints for DSLRs > 36mp
« Reply #30 on: February 21, 2020, 09:36:13 »
I found substituting the Z7 for D810 made a significant improvement for my macro work (typically 5-10X). Most of the improvrements probsbly are due to much lower amounts of camera shake, not so much the extra 9 MPix.

Empty magnifiction (leading to 'mush') is to be avoided in any critical system. Hence the need to match (pre-, post-) magnification, optics, and camera resolution to make an optimised system for a given application.

Airy

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Re: Optical constraints for DSLRs > 36mp
« Reply #31 on: February 21, 2020, 16:44:20 »
1) When I bought the D800, it did not make my lenses obsolete.

2) Once stopped down, good old MF lenses usually are able to make full use of the 36MP resolution, except maybe in some corners that rarely matter. The 105/2.5 is not the only one. I think a "blind test" challenge could settle the discussion here, better than statements by bloggers.

3) My first experience with a Z7 was in a store in Tokyo, and I asked if I could try out the lens I had with me: Noct Nikkor, AIS. The result was not for me to say "gosh, my dear oldie is obsolete", but "wow, more beautiful than ever" (the Z7 sensor is *really* good, not just hi-res). Later, I repeated the experiment with an old Summicron-R 50/2 (2nd generation). And, in both cases, I did not see lots of mush in places that really matter (close to the center or first third).

If I were to buy a Nikon Z, I would really hesitate between Z6 and Z7 because of the overall IQ of the latter (rather than resolution), given the strong impression that the Z7 made with my oldies. But I'd keep my lenses ! Zeiss, Leitz Canada, Voigtländer, and Nikon AI/AIS.

Of course, when shooting big flat detailed subjects like famous paintings in a museum or antique mosaics, expectations can be very different from mine.
Airy Magnien

Macro_Cosmos

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Re: Optical constraints for DSLRs > 36mp
« Reply #32 on: February 22, 2020, 10:21:34 »
It really depends on how one defines "acceptable". The corners of my stupidly expensive objective lenses aren't acceptable to me, so I only use the middle 4 segments out of 16, which is 25% of my 336MP D810 sensor. The rest is discarded as disgusting mush. Some might feel more comfortable, some won't.

To exemplify, here's a butterfly wing:

Full resolution: https://live.staticflickr.com/65535/49507079046_ae7e4d2445_o.jpg (downsampled by about 50%)
Centre is beautiful, corners put me off big time, and that's 50%, imagine how bad 100% is. There's weird comatic issues, softness, and smearing. This is a $950 objective lens. There are better options, but I'm not made out of money. Also the better options won't have good corners either, arguably worse actually, the high NA mitutoyo HR lenses have a smaller circle of sharpness. Some will say the corners look totally fine.

Such subject wouldn't matter too much when it comes to bad corners, however some are unforgiving, such as silicon wafers/chips:

https://live.staticflickr.com/65535/49559724711_8a0fa1f32e_o.jpg
You can see edge-to-edge sharpness with no visible drops, this is because I made a panorama of 10 shots where only 2 is truly necessary to showcase the entire chip. I can tolerate soft corners when it comes to butterfly wings; however for these chips, I want the absolute best from my camera. Can you imagine not being able to see what's in the corners? It defeats the purpose of such reproductions, I cannot and will not accept that.

I would have bought the Z50, but Nikon being Nikon decided the mirrorless D500 as their marketing claims doesn't need a shutter release input. I am baffled and have no idea what went through the engineers' mind. The Z50 doesn't tick the most important feature that I always assume is on a $1000+ camera body.  >:(  The cute little Nikon 1 J5 I bought for $150 AUD used doesn't have an input either, it fits in my daily travel pouch. Puts out really nice images.

Would be rather simple to DIY, but I'm not spending that time to get a feature that should be on a $1000+ AUD camera to begin with. Either they make a Z5 that's the true mirrorless counterpart of the D500, or I'll stick to my Dinosaur810. 


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Andor Zyla 5.5 sCMOS | Hamamatsu ORCA-Flash V3 | Nikon Z6 | Olympus Microscope

simsurace

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Re: Optical constraints for DSLRs > 36mp
« Reply #33 on: February 22, 2020, 16:27:31 »
Thanks for the examples and elaborations. I can follow all that. If you have a lens which produces mush in the corners there is no benefit in increasing resolution. What I struggle to understand is this notion (implied or not) of somehow being worse off with a higher res sensor. Maybe there is an unstated assumption about storage space and processing. And of course if people upgrade their camera to a higher res model they can be disappointed if they were hoping to be able to do certain things. But if higher-res sensors can be made at the same price point and as long as storage capacities continue to more or less evolve according to Moore's law, there is nothing much to worry about, even if there were no new lenses from now on.

Nice images of the butterfly wing and chip BTW!
Simone Carlo Surace
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longzoom

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Re: Optical constraints for DSLRs > 36mp
« Reply #34 on: February 22, 2020, 16:41:31 »


The butterfly's wing is perfectly sharp at the upper right and lower left corners, with some small loss of the resolution, as usual.  The rest is simply out of DOF, but, a very small detail is sharp, in the extreme lower right corner, inside tolerance of DOF. It looks like a very good lens, for me, at least.  LZ

Macro_Cosmos

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Re: Optical constraints for DSLRs > 36mp
« Reply #35 on: February 23, 2020, 11:56:46 »

The butterfly's wing is perfectly sharp at the upper right and lower left corners, with some small loss of the resolution, as usual.  The rest is simply out of DOF, but, a very small detail is sharp, in the extreme lower right corner, inside tolerance of DOF. It looks like a very good lens, for me, at least.  LZ
I think you're right, I've been quite conservative with the number of steps, my D810 is reaching 200k actuations. Maybe I should just nuke it and buy a D850/Z7, who knows?
That comatic aberration is especially weird, it's probably Oof mush that the program is trying to make sense of, thereby taking specular reflections as actual detail.

Here's one where the edges are sharp-ish as well. I somehow overlooked newby mistakes. I'll make another stack just for the sake of it.
Not saying the lens is bad, it's $1700 for what essentially is the size of a film canister. The corners just aren't "good".
You can see an example here: https://www.photomacrography.net/forum/viewtopic.php?t=41112
These are from totally manual setups with a resolution of 0.5 microns, so there's no way I missed the best depth of focus.


Thanks for the examples and elaborations. I can follow all that. If you have a lens which produces mush in the corners there is no benefit in increasing resolution. What I struggle to understand is this notion (implied or not) of somehow being worse off with a higher res sensor. Maybe there is an unstated assumption about storage space and processing. And of course if people upgrade their camera to a higher res model they can be disappointed if they were hoping to be able to do certain things. But if higher-res sensors can be made at the same price point and as long as storage capacities continue to more or less evolve according to Moore's law, there is nothing much to worry about, even if there were no new lenses from now on.

Nice images of the butterfly wing and chip BTW!
If we control for everything, then there isn't a real benefit. If not, obviously better ergonomics etc is the benefit.
If I have a lens that can only resolve a 4x4 unit pixel, then splitting this 4x4 into 4 segments of 2x2 pixels doesn't do anything. It's digital enlargement and on a pixel level, it's going to look less sharp.
High MP cameras (D850) will always cost more than their low MP (D780) counterparts with chronology being accounted for. So the question is, would that extra $1000+ that one is expected to pay worthwhile? When resolution is bottle-necked by the lens, no. For future proofing and potential newly released lenses to at least match the resolution? Perhaps, depends on how one values money, because next several years there's going to be a new toy that will make the current one cheaper.

You're not worse off, it's just pointless as the improvement will be marginal at best. What the author of the article fails to acknowledge likely due to the mirrorless bandwagon is "new F-mount lenses can always be made". Hell, we have several dozen existing ones that pair absolutely fine already! So >36MP is not pointless and certainly not "worse off", that's unless we're talking about the circle I'm in. A Mit 10x Apo is $900 new (works well with the D850), the HR version with an NA of 0.42 is $8000+, it couples well with a sensor that has 3x3um pixels (Sony a7R4 has a pitch of about 3.7um).

However at 20x, all this is turned upside down. The 20x with an NA of 0.42 resolves about 6.1x6.1um pixels, the D810 works pretty well with 4.87x4.87um, how about higher? Not so much. One isn't worse off, there's just close to zero improvements image-wise. If we go to Mit's 50x NA0.55, then it's 9x9um, the "just don't zoom in" category. It can be said that one is better off cropping into the 20x 0.42 and keeping that at least $800 for a used copy that might not work at all. Unless there's a commercial and scientific need for big fat objectives with adequate WA and high NA, all at actually acceptable prices, the D810 is pretty much topped out when it comes to image quality.

All this changes with the introduction of pixel shift though, which is capable to circumvent this resolution matching fiasco and pop out beautiful detail, even on lenses that can't resolve its pixels. So at the end of the day, higher MP is still justified regardless of the author's rationalism or cherrypicked charts. Oh, downsampling is always an option too, I downsample my 36MP shots into 18MP ones. Goodbye mushy corners.
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Andor Zyla 5.5 sCMOS | Hamamatsu ORCA-Flash V3 | Nikon Z6 | Olympus Microscope