Infinity objective
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- Joaquim F.
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Teles
Hello, now I know why the lateral areas in the pictures do not come out as sharp as they should. Rik, thank you very much for the explanation!
In the Nikon literature is recommended a distance of 10 - 20 cm between the microscope objective lens and tube, and warn of image degradation over distance, the problem with the Teles is that it is not known which is the distance to the optical center, may be the position of the diaphragm? but in that case you cannot mount the microscope objective at very much distance without vignetting.
Probably the solution, apart from the original Nikon lens, is using a lens with a standard design, something like an enlarger or process lens?
The diagram from Edmundoptics show a 30mm frontal aperture for the 200mm Nikon tube lens, that is something like a f/6.7 optics, is not necessary a large aperture lens, in my Nikon 200/4 can close to f/8 without great apparent changes in DOF or resolution, and vignetting too with a short extension.
best regards
joaquim
In the Nikon literature is recommended a distance of 10 - 20 cm between the microscope objective lens and tube, and warn of image degradation over distance, the problem with the Teles is that it is not known which is the distance to the optical center, may be the position of the diaphragm? but in that case you cannot mount the microscope objective at very much distance without vignetting.
Probably the solution, apart from the original Nikon lens, is using a lens with a standard design, something like an enlarger or process lens?
The diagram from Edmundoptics show a 30mm frontal aperture for the 200mm Nikon tube lens, that is something like a f/6.7 optics, is not necessary a large aperture lens, in my Nikon 200/4 can close to f/8 without great apparent changes in DOF or resolution, and vignetting too with a short extension.
best regards
joaquim
Last edited by Joaquim F. on Tue May 04, 2010 3:48 pm, edited 2 times in total.
Rik, I'm not sure whether your insightful answer was in response to my post or Chris R.'s, but regardless, thanks for it!
May I apologize for being thick and ask you to enlarge upon your analysis in relation to Figure 2, labeled "Finite and Infinity Optical Systems," at this Website: http://www.microscopyu.com/articles/optics/cfintro.html
In this diagram, the tube lens in the infinity system need have no greater diameter than the infinity objective, which to me makes intuitive sense. And a great many inexpensive lenses should be at their optical best when just that portion is used--it would appear to be quite easy to select a lens with a large enough aperture not to involve using its edge portion.
I'm sure I'm missing something. (And for me the point is moot, since I have a pretty good set of finite objectives--but I always appreciate having my misunderstandings corrected.)
Thanks again,
--Chris S.
May I apologize for being thick and ask you to enlarge upon your analysis in relation to Figure 2, labeled "Finite and Infinity Optical Systems," at this Website: http://www.microscopyu.com/articles/optics/cfintro.html
In this diagram, the tube lens in the infinity system need have no greater diameter than the infinity objective, which to me makes intuitive sense. And a great many inexpensive lenses should be at their optical best when just that portion is used--it would appear to be quite easy to select a lens with a large enough aperture not to involve using its edge portion.
I'm sure I'm missing something. (And for me the point is moot, since I have a pretty good set of finite objectives--but I always appreciate having my misunderstandings corrected.)
Thanks again,
--Chris S.
- rjlittlefield
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Sure -- their illustration is drawn wrong!Chris S. wrote:May I apologize for being thick and ask you to enlarge upon your analysis in relation to Figure 2, labeled "Finite and Infinity Optical Systems," at this Website: http://www.microscopyu.com/articles/optics/cfintro.html
In their illustration, different portions of the objective are being used for different points on the object.
If drawn correctly, the entire objective is used for all points on the object. The resulting parallel bundles are all aligned with each other at the exit pupil of the objective, but then diverge from each other in proportion to each object point's distance from the optical axis.
Like this:
My earlier posting was in response to your question, by the way. It's a good question -- produces much insight.
--Rik
- rjlittlefield
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Chris, you're very welcome. As I've said before, I learn a lot in trying to write these explanations.
By the way, I have to give credit here to the LINOS Photonics WinLens program. I have found it very valuable in helping to test ideas and to prepare illustrations. The program is fairly simple to use, and since it's in the business of tracing rays instead of fudging to illustrate a concept, it doesn't let me get away with hand-waving arguments.
--Rik
By the way, I have to give credit here to the LINOS Photonics WinLens program. I have found it very valuable in helping to test ideas and to prepare illustrations. The program is fairly simple to use, and since it's in the business of tracing rays instead of fudging to illustrate a concept, it doesn't let me get away with hand-waving arguments.
--Rik
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Joaquim, Chris and Pau thank you.
Last night I did some test with the Nikon CFI60 10/0.25 and the CFN 10/0.3 WI (without the WI tipping).
Single shot (50% crop) with Nikon CFI60 10/0.25 and 110mm between the objective shoulder and the Vivitar 200mm lens:
Single shot (50% crop) with Nikon CFI60 10/0.25 and 50mm between the objective shoulder and the Vivitar 200mm lens:
Single shot (50% crop) with Nikon CFN 10/0.30 WI:
Rogelio
Last night I did some test with the Nikon CFI60 10/0.25 and the CFN 10/0.3 WI (without the WI tipping).
Single shot (50% crop) with Nikon CFI60 10/0.25 and 110mm between the objective shoulder and the Vivitar 200mm lens:
Single shot (50% crop) with Nikon CFI60 10/0.25 and 50mm between the objective shoulder and the Vivitar 200mm lens:
Single shot (50% crop) with Nikon CFN 10/0.30 WI:
Rogelio
- rjlittlefield
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Rik, there are not significant differences, a little more small details with the Nikon CFI60 10/0.25 and 110mm between the objective shoulder and the Vivitar 200mm lens.rjlittlefield wrote:At this scale, I see slight differences in framing and exposure, but nothing that would make me prefer one over another. Are there significant differences when you look closer?
--Rik
Rogelio
- rjlittlefield
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- Joaquim F.
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Tube lens
Hi, I found this diagram of a zeiss tube lens, it may be as simple as it seems?
http://fermionlattice.wdfiles.com/local ... sstubelens
Regards
Joaquim
http://fermionlattice.wdfiles.com/local ... sstubelens
Regards
Joaquim
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Re: Tube lens
If it is that simple, would an achromatic +5 diopter close up lens (+5D = 200mm) also function as a tube lens?Joaquim F. wrote:Hi, I found this diagram of a zeiss tube lens, it may be as simple as it seems?
http://fermionlattice.wdfiles.com/local ... sstubelens
Joaquim
(Hi. First post. Have been lurking and reading for a couple of weeks).
- rjlittlefield
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Re: Tube lens
Welcome aboard!ChrisLilley wrote:If it is that simple, would an achromatic +5 diopter close up lens (+5D = 200mm) also function as a tube lens?
It will certainly work to some extent. You might have to reverse it to get best quality, since those lenses are normally designed to have the short conjugate on the front.
I am a little surprised at the simplicity of the Zeiss tube lens. This appears to be a singlet or possibly a cemented doublet (internal surfaces not shown), plus a retaining ring. I wonder if there is more lurking behind the apparent simplicity of the design. Aspheric, perhaps?
--Rik
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Just received and preliminary tested a Nikon CF Plan 10X 0.30 infinity/0 WD 16.5.
Following the Rogelio's setup, I focused it to the camera sensor whith an Olympus OM 200mm f4. The objective was mounted in a Zeiss Standard microscope whithout head and the camera and lens vertically suspended over it.
Here my first test images and findings
http://www.photomacrography.net/forum/v ... 9281#59281
Rick, thanks for your diagrams and explanations: I finally understood what an infinite objective is.
Following the Rogelio's setup, I focused it to the camera sensor whith an Olympus OM 200mm f4. The objective was mounted in a Zeiss Standard microscope whithout head and the camera and lens vertically suspended over it.
Here my first test images and findings
http://www.photomacrography.net/forum/v ... 9281#59281
Rick, thanks for your diagrams and explanations: I finally understood what an infinite objective is.
Pau