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- rjlittlefield
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- rjlittlefield
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OK, thanks.
The vignette is due to the tube lens, then. The Tamron's entrance pupil is too small and far back so it fights with the exit pupil of the objective. If the vignette is troublesome, you can get rid of it by switching to a Raynox tube lens setup such as shown at http://www.photomacrography.net/forum/v ... hp?t=35350 .
By the way, I'm a little puzzled by the description "Nikon CF Plan 50X SLWD" used in combination with a tube lens. The CF's that I know are finite. (Infinites are CFI or CFI60.) I assume you've checked that the objective is marked with an infinity symbol and not 160 for tube length.
--Rik
The vignette is due to the tube lens, then. The Tamron's entrance pupil is too small and far back so it fights with the exit pupil of the objective. If the vignette is troublesome, you can get rid of it by switching to a Raynox tube lens setup such as shown at http://www.photomacrography.net/forum/v ... hp?t=35350 .
By the way, I'm a little puzzled by the description "Nikon CF Plan 50X SLWD" used in combination with a tube lens. The CF's that I know are finite. (Infinites are CFI or CFI60.) I assume you've checked that the objective is marked with an infinity symbol and not 160 for tube length.
--Rik
That's so interesting! I assumed that the focal length was the issue. I did notice that stopping down the lens produced a more severe vignette, though, so your explanation makes sense.
Ignoring the vignette, would a Rayonox provide any other advantages? If not, I don't mind cropping a little.
The objective is definitely infinity corrected. Here is a link:
https://www.bostonind.com/nikon-cf-plan ... e-mue30501
I do appreciate you asking, though. When I first started experimenting with microscope objectives I was using a coverslip-corrected objective and it took me way too long to realize.
Ignoring the vignette, would a Rayonox provide any other advantages? If not, I don't mind cropping a little.
The objective is definitely infinity corrected. Here is a link:
https://www.bostonind.com/nikon-cf-plan ... e-mue30501
I do appreciate you asking, though. When I first started experimenting with microscope objectives I was using a coverslip-corrected objective and it took me way too long to realize.
- rjlittlefield
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Ah, right, thanks for the reminder. It slipped my mind that I actually have a couple of that series. Before I got Mitutoyo objectives, I had good success with the Nikon CF Plan 50X NA 0.55 inf/0 EPI ELWD (8.7 mm) pushed down to 25X with a 100 mm tube lens, http://www.photomacrography.net/forum/v ... 825#103825 .cube-tube wrote:The objective is definitely infinity corrected. Here is a link:
https://www.bostonind.com/nikon-cf-plan ... e-mue30501
--Rik
- rjlittlefield
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Probably not, and many people find Raynox setups to be less convenient than telephoto due to overall length and other handling issues. If the vignette is not troublesome and you're otherwise happy, no need to mess with a good thing.cube-tube wrote:Ignoring the vignette, would a Rayonox provide any other advantages?
Sometimes a vignette will degrade alignment between frames when stacking, because the stacking software locks onto the vignette instead of other image content that belongs to the subject. If you have trouble with that, then consider making cropped copies of the source images, and stack the crops. If you're using Zerene Stacker, you can do that on the fly using Options > Preferences > Preprocessing > Image Pre-cropping.If not, I don't mind cropping a little.
--Rik
- carlos.uruguay
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