Archive 2015 · A thinner sensor stack may be possible after all!
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p.54 #1 · A thinner sensor stack may be possible after all!
retrofocus wrote:
I would expect the Summicron 35 versions - all BUT the ASPH which will likely continue to suck on A7 bodies even after Kolari modification! - to work well. I am using version IV, 7-element 35/2 very effectively on my unmodified A7R. Super sharp and zero corner issues with this lens on the camera body. My recommendation is to look out for this 35/2 version - sometimes you find decent deals for it online, but you might have to wait a bit.
Have you seen any tests of the new modified for digital 35 cron ASPH? I have hopes for that lens on a modified camera, but the one that was not modified for digital would not be suitable for me even on a modified camera. I know Fred tested the new one on an unmodified camera and it was much better, but still wasn't what I would want. The combo of the modified for digital lens and the modified camera, however, I think might actually work pretty well.
p.54 #2 · A thinner sensor stack may be possible after all!
Steve Spencer wrote:
Have you seen any tests of the new modified for digital 35 cron ASPH? I have hopes for that lens on a modified camera, but the one that was not modified for digital would not be suitable for me even on a modified camera. I know Fred tested the new one on an unmodified camera and it was much better, but still wasn't what I would want. The combo of the modified for digital lens and the modified camera, however, I think might actually work pretty well.
Nops, I only tested the 35/2 ASPH (previous version) - horrible, and then I simply moved to the CV 35/1.2 II and even better 35/2 Summicron 7-element. I believe all the ASPH versions are excellent performers on M cameras but should be considered only very, very cautiously for any A7 series camera - modified or unmodified.
p.54 #3 · A thinner sensor stack may be possible after all!
Thanks for the insights!
Retrofocus, if you had any full-size examples of the Summicron 35 IV on the A7r @f/2 at infinity that you could share, it would be of tremendous help for my decision.
p.54 #4 · A thinner sensor stack may be possible after all!
Greetings,
I'm querying if anyone here with a kolari modded Sony A7Rii has tried any of the Wide Angle Zeiss ZM lenses, and if so, how much of a difference has the mod made to wide open performance in the corners?
I'm mainly interested in any users who have experience with the 18mm Distagon, 25mm Biogon and 28mm Biogon ZM lenses.
Much appreciated!😀
p.54 #5 · A thinner sensor stack may be possible after all!
Does somebody have a A7rii Kolari?
Also for what it's worth, I did not care for the v3, and returned it for v2, which I like very much on A7. I did several hours of research online regarding the antireflection treatment, which is widely used for telescopes. Glass sellers actually had different products tuned for different ray angles which implies the treatment does not deal with all angles the same. Kolari wondered if such a thin filter would show it. I never had a reflection problem, so the v3 helped nothing for me in that respect.
My ZM 35/2 was pretty decent on v1, but I hated it on v3. I'm not sure the v2 is quite as good with that lens as the v1 but it's close.
p.54 #6 · A thinner sensor stack may be possible after all!
uhoh7 wrote:
Does somebody have a A7rii Kolari?
Also for what it's worth, I did not care for the v3, and returned it for v2, which I like very much on A7. I did several hours of research online regarding the antireflection treatment, which is widely used for telescopes. Glass sellers actually had different products tuned for different ray angles. I never had a reflection problem.
My ZM 35/2 was pretty decent on v1, but I hated it on v3. I'm not sure the v2 is quite as good with that lens as the v1 but it's close.
Kolari was very good about swaping out the v3 ...Show more →
Hi Charlie,
You just didn't have the colors adjusted adequately for the V3. Both Michael Meyer as I recall likes it on his A7r and I like it on my A7r.
p.54 #7 · A thinner sensor stack may be possible after all!
naturephoto1 wrote:
Hi Charlie,
You just didn't have the colors adjusted adequately for the V3. Both Michael Meyer as I recall likes it on his A7r and I like it on my A7r.
Rich
Had nothing to do with color Rich. I did not bother even trying to deal with that because of the way the lens was working. It's an especially tough one though.
p.54 #8 · A thinner sensor stack may be possible after all!
uhoh7 wrote:
Had nothing to do with color Rich. I did not bother even trying to deal with that because of the way the lens was working.
Hi Charlie,
Sorry. I was referring to your liking of the color output that you had been seeing with your lenses with the V3 sensor stack cover and you reverted back to the V2. As I have mentioned, though Michael and I like the sensor color, etc. that we are seeing with the V3 sensor stack cover.
p.54 #9 · A thinner sensor stack may be possible after all!
naturephoto1 wrote:
Hi Charlie,
Sorry. I was referring to your liking of the color output that you had been seeing with your lenses with the V3 sensor stack cover and you reverted back to the V2. As I have mentioned, though Michael and I like the sensor color, etc. that we are seeing with the V3 sensor stack cover.
Rich
Right, I don't doubt you guys have the colors great now on v3. I feel the treatment may compromise the high ray angles going into the edges on some lenses. I can't prove it because I don't have the time or the careful shots. What I know: I expected v1 performance level which I knew pretty well, really considered it a given but test shots really hit me.
I'm not sure if there is any visible difference there (UPDATE looks like there is), as I based my impression on the ZM at faster speeds. I certainly could be mistaken. But there was no doubt in my mind after a bunch of shots at the time, and I did not want to return the camera. I felt I had to. The v2 I thought really was not quite v1 but close enough.
Again colors had nothing to with it.
Digging back I had learned (copied form correspondence):
When I research AR coating I come across it's effects on high incidence rays over and over:
"Layer thicknesses are chosen to produce destructive interference in the beams reflected from the interfaces, and constructive interference in the corresponding transmitted beams. This makes the structure's performance change with wavelength and incident angle, so that color effects often appear at oblique angles." this from wikipedia.
"An unusual type of anti-reflection coating is one consisting of a very thin layer of some strongly absorbing material. The thickness can be only some tens of nanometers, i.e., far less than usually required for lossless AR coatings, as strong imaginary components of the propagation constant of such media lead to substantial phase changes. The incident light is largely absorbed by such structures, rather than transmitted."
What these quotes establish is that incident light angles are an issue with AR coatings and thinness doe not preclude this.
Here I had a chart with various ray angles of RF lenses.
Here we can see the sorts of extreme ray angles, near 50 degrees, we are dealing with in lenses like the ZM 18/4. So the cover glass must deal with the entire gamut from 0 to 50. At one point Leica techs felt this was not possible with a digital sensor, that's how hard it is, I guess.
Here from another article which applies specifically to cover glass:
The thickness of each layer is between 20 and 80 nm, all of them are quite easily achievable with various deposition process. The influence of optical aperture on peak transmittance is acceptable as it is in the range of 5 nm shift with a 20 degree angle.
Based on this it is entirely possible, perhaps probable that the AR coating of v3 degrades high incident angle light transmission vs v2.
Probably the most controversial thing I have contended in the past is thin filter improvement to some SLR lenses, which many poo pooed. But I'd point out that that regardless of whether my theory was correct, my eye was probably pretty good, perhaps just seeing the lack of AA filter as opposed to superior ray angle performance. This only applies to A7 and A7ii of course. But there is no question removal of the AA filter improves the image, i.e. there is a real effect, maybe just that, maybe more. Glass in the path tests suggest in can be more.
So again, if you are looking for the best WA RF performance the v2 may be a safer I bet. I believe it is.
p.54 #11 · A thinner sensor stack may be possible after all!
Reviving a dead thread.
I just tested all my 35mm's on the NKIR and stock sensor stacks, as I debate what to sell.
Laowa 35mm Argus
CV35mm Nokton II
ZM35mm Distagon
Sony 35mm GM
Contax G 35mm Planar
CV35mm APO-Lanthar
CV35mm Color-Skopar
Spoilers: they're each great on exactly the sensor stack you'd expect and weak on the other. The Laowa is as sharp on the stock sensor stack at f/.95 as the CV Nokton is on the thin stack at f/1.2. The ZM is basically as good on the thin stack as the GM is on stock. But notably, the GM is least affected by the sensor stack. There's a slight different wide open, but at f/2.8 and beyond, I can't tell the difference.
The Color Skopar is tiny and only for thin stacks. The unexpected one is the Contax G, which is surprisingly resilient regardless of sensor stack. It's a weird lens though. It's weird and great in the way the Loxia 35mm is weird and great, but also much smaller.
I'm debating still what crops/comparisons to share, since we're talking about seven lenses across two bodies, but the results have been useful. Requests welcome.
I'm probably now finally content to let go of my ZM? Struggling with the Nokton. Will I be content with the CV Color Skopar as my only thin sensor mod 35mm len? Not sure. Or maybe I need the Nokton III.
