It's easy to check whether the entrance pupil of a lens moves when focusing. Set it to a focus on a needle stuck vertically in a piece of styrofoam, near the edge of the viewfinder frame. Stop the lens way down and stick another needle somewhere exactly behind the first needle, according to the imag...

Those look quite good. I have found that the best tube lenses are those designed for a format a little larger than the taking format; my "workhorse" tube lens for micro Four Thirds is a Nikon 80-200mm zoom, and for FF the Mamiya 645 Apo 200mm, the Mamiya 67 Apo-Sekor 250mm, and the Pentax 67 M* 300m...

Chris, that's very useful info about the Mejiro Gnossen FL0530. I'm surprised to see that the range of corrected wavelengths does not include violet or deep red. This suggests there might be CA in some subjects. Have you seen any? Also, can you recommend a vendor? Chendata is sold out. This is the ...

Chris, that's very useful info about the Mejiro Gnossen FL0530. I'm surprised to see that the range of corrected wavelengths does not include violet or deep red. This suggests there might be CA in some subjects. Have you seen any?

Also, can you recommend a vendor? Chendata is sold out.

"I don't think a 50x HR 0.75 NA is going to fall (gently?) from the sky at me anytime for an unreal price :D" Well, you already have something better than that (same NA and with a FOV more than twice as large), and for $100! The 20x/0.75s are awesome but there is some difference between 1mm of work...

"I don't think a 50x HR 0.75 NA is going to fall (gently?) from the sky at me anytime for an unreal price "

Well, you already have something better than that (same NA and with a FOV more than twice as large), and for $100!
http://www.photomacrography.net/forum/v ... 07#p295907

Remember that the objective is stopping down the lens very much more than the camera thinks, and so the automatically calculated step size, based on the chosen step setting and the fully open tube lens aperture, is much too small for the actual optical arrangement.

I hope you have a lot of fun with it. I predict you will soon need to buy some new hard drives jejeje.

Chris S., this is great data, nice to have real numbers. And what a generous help you have been giving to forum members by vetting these objectives!

Was it this one Lou? https://www.photomacrography.net/forum/viewtopic.php?t=41684#p262323 That one, and other diatom shots like it were done with a ,50x Mitty pushed down to 33x on a 135mm tube lens. Cheers Maybe that was it. That's a lovely shot, similar to the one I am thinking of. But I thought ...

Sometimes there are reasonably priced 10x 0.50 objectives on eBay. I found and bought an affordable Nikon 10x 0.50 S Fluor with a working distance of 1.2mm.

Steve, a long time ago I thought you had posted here a reflected-light photo of a singe diatom on edge, on a glass coverslip or slide, beautifully lit like a macro, using a 100x Mitu?? My recollection could be bad of course. I can still see the photo in my head, though....it was really nice.

Well, I dropped one from waist height onto a bare concrete floor. I think it is de-centered now, but still produces pretty good images overall.

Great additional information! Yes, the main constraint is the amount of focus throw available. The 45-175mm lens is particularly good for that, relative to other lenses I've tested. I have not tested most of the other zooms mentioned. And yes, this method does produce incredibly fast stacks, and is ...

Looks expensive and interesting.