Olympus Projection Eyepieces turn apos into achros (not clickbait)
Moderators: rjlittlefield, ChrisR, Chris S., Pau
-
- Posts: 1527
- Joined: Mon Jan 15, 2018 9:23 pm
- Contact:
Olympus Projection Eyepieces turn apos into achros (not clickbait)
What is going on here?
Am I doing something stupidly wrong or are these UIS-era projection eyepieces simply incompatible with modern UIS2 objectives?
Specification:
Nikon Z6, 24MP BSI, 35mm format, with OLPF.
Original photomicro L and OM>Z adaptor.
Universal condenser configured for Kohler illumination, superwide trinocular head.
100W halogen light source.
Target is a precision-made 400lp/mm resolution chart, coverslip adhered to the chart via matching RI liquid.
All post-processing was removed. No sharpening etc.
Virtually no CA with direct projection, all kinds of CA with a silly colour pattern when PEs are used. I tried to convince myself that I'm doing something stupidly wrong but I cannot think of an error.
Any advice on how to troubleshoot this? I will try and get more examples using different objectives.
Edit: So these were designed during the film days. A common issue with manual, vintage lenses is softness and aberrations due to modern sensor's window. The Z6 has a very thin one but with a microscope objective, even that piece of glass could be too much. Another reason is that these projection eyepieces are not actually apochromatic. Combined with a lowish magnification, the issue is exacerbated. I tried 20x and 60x, the eyepieces still bring chromatic aberration, but it was no where near as bad. What do you know? It was worse with a 4x objective.
Am I doing something stupidly wrong or are these UIS-era projection eyepieces simply incompatible with modern UIS2 objectives?
Specification:
Nikon Z6, 24MP BSI, 35mm format, with OLPF.
Original photomicro L and OM>Z adaptor.
Universal condenser configured for Kohler illumination, superwide trinocular head.
100W halogen light source.
Target is a precision-made 400lp/mm resolution chart, coverslip adhered to the chart via matching RI liquid.
All post-processing was removed. No sharpening etc.
Virtually no CA with direct projection, all kinds of CA with a silly colour pattern when PEs are used. I tried to convince myself that I'm doing something stupidly wrong but I cannot think of an error.
Any advice on how to troubleshoot this? I will try and get more examples using different objectives.
Edit: So these were designed during the film days. A common issue with manual, vintage lenses is softness and aberrations due to modern sensor's window. The Z6 has a very thin one but with a microscope objective, even that piece of glass could be too much. Another reason is that these projection eyepieces are not actually apochromatic. Combined with a lowish magnification, the issue is exacerbated. I tried 20x and 60x, the eyepieces still bring chromatic aberration, but it was no where near as bad. What do you know? It was worse with a 4x objective.
- blekenbleu
- Posts: 147
- Joined: Sat May 10, 2008 5:37 pm
- Location: U.S.
- Contact:
Re: Olympus Projection Eyepieces turn apos into achros (not clickbait)
Scarodactyl reported similar disappointment with Nikon PEs:Macro_Cosmos wrote: ↑Tue Jan 17, 2023 3:33 amVirtually no CA with direct projection, all kinds of CA with a silly colour pattern when PEs are used.
viewtopic.php?t=42625
Better results with direct projection and even afocal.
Metaphot, Optiphot 1, 66; AO 10, 120, and EPIStar 2571
https://blekenbleu.github.io/microscope
https://blekenbleu.github.io/microscope
- rjlittlefield
- Site Admin
- Posts: 23626
- Joined: Tue Aug 01, 2006 8:34 am
- Location: Richland, Washington State, USA
- Contact:
Re: Olympus Projection Eyepieces turn apos into achros (not clickbait)
That explanation doesn't work for me. The problem with thick window on the sensor appears at wide effective aperture, as seen by the sensor, when a wide cone of light has to traverse the window glass. Thick cover glass at the subject is a problem for objectives, for the same reason. But at the sensor objectives give a narrow cone of light, typically f/14 to f/20.Macro_Cosmos wrote: ↑Tue Jan 17, 2023 3:33 amA common issue with manual, vintage lenses is softness and aberrations due to modern sensor's window. The Z6 has a very thin one but with a microscope objective, even that piece of glass could be too much.
--Rik
-
- Posts: 1636
- Joined: Sat Apr 14, 2018 10:26 am
Re: Olympus Projection Eyepieces turn apos into achros (not clickbait)
That's a bummer. I thought it was really weird when I got those results on the Nikon PL eyepieces, and definitely would not have expected it to be that bad in the infinity era.
I wonder how it compares to a high quality teleconverter.
I wonder how it compares to a high quality teleconverter.
Re: Olympus Projection Eyepieces turn apos into achros (not clickbait)
"I wonder how it compares to a high quality teleconverter."
I use teleconverters as a matter of course, even with finite objectives, and good ones work very well.
I use teleconverters as a matter of course, even with finite objectives, and good ones work very well.
-
- Posts: 84
- Joined: Tue Nov 01, 2016 11:53 pm
Re: Olympus Projection Eyepieces turn apos into achros (not clickbait)
How do they look when mag is normalized?
-
- Posts: 1527
- Joined: Mon Jan 15, 2018 9:23 pm
- Contact:
Re: Olympus Projection Eyepieces turn apos into achros (not clickbait)
Great point. This is consistent with my observations as well, those manual lenses get really good when stopped down just a tad.rjlittlefield wrote: ↑Tue Jan 17, 2023 10:35 amThat explanation doesn't work for me. The problem with thick window on the sensor appears at wide effective aperture, as seen by the sensor, when a wide cone of light has to traverse the window glass. Thick cover glass at the subject is a problem for objectives, for the same reason. But at the sensor objectives give a narrow cone of light, typically f/14 to f/20.Macro_Cosmos wrote: ↑Tue Jan 17, 2023 3:33 amA common issue with manual, vintage lenses is softness and aberrations due to modern sensor's window. The Z6 has a very thin one but with a microscope objective, even that piece of glass could be too much.
--Rik
I am dumbfounded and cannot come up with a good explanation.
- PEs were designed during the film era and the optics/formula/layout were not as good
This could work but it sounds too lazy to me.
I was told that Zeiss ones suffer from similar issues.
Any ideas? I do not have a UIS-era 10x objective, however, I know someone who does and I might be able to convince him to try it out.
I did digitally zoom in. The XApo is the clear winner but the SApo is not any worse. There are faint hints of green LoCA. Such targets are challenging anyway, the CA surely will not present itself with normal imaging.
Here is the duo.
Re: Olympus Projection Eyepieces turn apos into achros (not clickbait)
In Nikon scopes the projectives PL and PLI are dedicated for CF and CFI series respectively and according to the maker not interchangeable.
I think that we know the reason: CF series aren't really "Chroma Free" (full corrected in our jargon) but they need a small compensation done at the eyepiece, this is why their CFW eyepieces show a faint orange halo at its field limit (typical of compensating eyepieces).
I guess that PL and "CF photo" photoeyepieces of that era also will do
This is also shown at the graph posted by peter-h at
https://www.mikroskopie-forum.de/index. ... #msg166258
quoted by Scarodactyl at
https://www.microbehunter.com/microscop ... e64#p80756
and here previously discussed, for example at viewtopic.php?p=234051#p234051
Could be possible that Olympus UIS had the same approach (small non declared CDM compensation) not present in UIS2?
Could you try other brands' non compensating projective photoeyepieces like Nikon PLI and Zeiss P 2.5?
If you shot afocally through one of the visual eyepieces, do you see the same issue?
I think that we know the reason: CF series aren't really "Chroma Free" (full corrected in our jargon) but they need a small compensation done at the eyepiece, this is why their CFW eyepieces show a faint orange halo at its field limit (typical of compensating eyepieces).
I guess that PL and "CF photo" photoeyepieces of that era also will do
This is also shown at the graph posted by peter-h at
https://www.mikroskopie-forum.de/index. ... #msg166258
quoted by Scarodactyl at
https://www.microbehunter.com/microscop ... e64#p80756
and here previously discussed, for example at viewtopic.php?p=234051#p234051
Could be possible that Olympus UIS had the same approach (small non declared CDM compensation) not present in UIS2?
Could you try other brands' non compensating projective photoeyepieces like Nikon PLI and Zeiss P 2.5?
If you shot afocally through one of the visual eyepieces, do you see the same issue?
Pau
-
- Posts: 1636
- Joined: Sat Apr 14, 2018 10:26 am
Re: Olympus Projection Eyepieces turn apos into achros (not clickbait)
Though this is appealing I don't think this is the correct explanation. My tests were done on nominally fully compatible parts and only direct projection yielded good results--certainly the pl eyepieces were not correcting anything in the bd plans' image. Nikon cfw and cfwn viewing eyepieces do have that faint ring but they also add some chroma, not by design but as a limitation. They also sold a much more expensive better-corrected eyepiece variant but they are rare since nobody bought them.Pau wrote: ↑Thu Jan 19, 2023 10:01 amIn Nikon scopes the projectives PL and PLI are dedicated for CF and CFI series respectively and according to the maker not interchangeable.
I think that we know the reason: CF series aren't really "Chroma Free" (full corrected in our jargon) but they need a small compensation done at the eyepiece, this is why their CFW eyepieces show a faint orange halo at its field limit (typical of compensating eyepieces).
The quoted graph shows some chroma in the tested nikon objective but it's not an apo or even a fluorite so it is expected that some amount would be present.
The pl and pli eyepieces are quite cross-compatible incidentally, they went out of their way to make them so (the cfuw/cfuwn and cfiuws even have their notches in the same positions so new ones fit on old heads). The infinity 45mm parfocal cf and cfi60 lines still coexist and share parts. From my limited testing the pli eyepiece I tried seemed to give cleaner results with the finite objectives too--certainly the intermediate pl-2.5xa did though I am not sure what system it was designed for. I wish I still had all the parts in front of me and could run more tests, maybe I'll have a chance again in the future.
-
- Posts: 423
- Joined: Fri Mar 01, 2013 1:43 am
- Location: Lund, Sweden
Re: Olympus Projection Eyepieces turn apos into achros (not clickbait)
I've managed to snag a pair of these 10x CFD eyepieces, would be very interesting to compare them in an afocal setup against the CF PL 2.5x.Scarodactyl wrote: They also sold a much more expensive better-corrected eyepiece variant but they are rare since nobody bought them.
-
- Posts: 1527
- Joined: Mon Jan 15, 2018 9:23 pm
- Contact:
Re: Olympus Projection Eyepieces turn apos into achros (not clickbait)
Not the easiest to test since the projection eyepiece sits in the U-SPT, I doubt the other two fit. The Zeiss ones look big, like actual eyepieces.
No (visible) chromatic aberration if I shot through the 10x eyepiece (SWH10x-H 26.5mm FN), I will try directly through the port sometime next week.
More comparisons to come.
-
- Posts: 1636
- Joined: Sat Apr 14, 2018 10:26 am
Re: Olympus Projection Eyepieces turn apos into achros (not clickbait)
Yeah, the PE eyepieces are what, 25mm? You could fit the 23mm version of the pli 2.5x but I don't think they made a 23mm version of the 2x.
I guess you can always direct project onto a smaller sensor.
I guess you can always direct project onto a smaller sensor.
-
- Posts: 84
- Joined: Tue Nov 01, 2016 11:53 pm
Re: Olympus Projection Eyepieces turn apos into achros (not clickbait)
I meant, how would they look if the apparent magnification is the same for all the images? e.g. adding 5x to the direct projection and comparing with the PE5x. And where are we looking at within the FN? I presume the comparison is somewhere in the middle, but if it's on the periphery I'm not so sure.
I did digitally zoom in. The XApo is the clear winner but the SApo is not any worse. There are faint hints of green LoCA. Such targets are challenging anyway, the CA surely will not present itself with normal imaging.
Re: Olympus Projection Eyepieces turn apos into achros (not clickbait)
Do these CFD show a faint yellow-orange halo at the limit of the visual field?viktor j nilsson wrote: ↑Thu Jan 19, 2023 10:26 amI've managed to snag a pair of these 10x CFD eyepieces, would be very interesting to compare them in an afocal setup against the CF PL 2.5x.Scarodactyl wrote: They also sold a much more expensive better-corrected eyepiece variant but they are rare since nobody bought them.
If not, this could definitively invalidate my hypothesis
Pau
-
- Posts: 423
- Joined: Fri Mar 01, 2013 1:43 am
- Location: Lund, Sweden
Re: Olympus Projection Eyepieces turn apos into achros (not clickbait)
Did a quick test. 10x 0.30 CFN plan fluor objective. Cover slip and oil on slide.Pau wrote: ↑Fri Jan 20, 2023 9:58 amDo these CFD show a faint yellow-orange halo at the limit of the visual field?viktor j nilsson wrote: ↑Thu Jan 19, 2023 10:26 amI've managed to snag a pair of these 10x CFD eyepieces, would be very interesting to compare them in an afocal setup against the CF PL 2.5x.Scarodactyl wrote: They also sold a much more expensive better-corrected eyepiece variant but they are rare since nobody bought them.
If not, this could definitively invalidate my hypothesis
I think it's safe to say that Nikon intended the CFN objectives to be fully corrected. And that the orange fringe on the CFW eyepieces is not a design feature, but a sign of them being optically inferior.
Thanks for pushing me to do this, hadn't really realized how good the CFDs were.