Rik,rjlittlefield wrote: ↑Wed Jan 29, 2025 12:19 amThanks for the picture of the objectives.
The constant notation 160/0.17 describes "finite" objectives (no tube lens required) that are designed to look through cover glass that is 0.17 mm thick. Cover glass doesn't really matter for the 10X and 4X objectives, but the 40X has to have it or the image quality will suffer badly.
The notations 100/1.25, 40/0.65, 10/0.25, and 4/0.10 all describe magnification/NA. So, your 40X objective is NA 0.65, and that will have DOF of only about 0.001 mm.
The 100X objective is "oil immersion" and must be used with oil or the image quality will be trash. The oil layer between the objective and cover glass is essentially another refracting element of the lens.
--Rik
I guess that cover glass is like the internal UV filter in a super-telephoto lens - a part of the optical formula. I'm a bit concerned about that DOF of 0.001 mm. Yesterday I read about all the mentioned (by Chris S.) stepper hardware (+DYI & others), and decided the WeMicro was the best fit for the microscope, because it could easily also be used with my existing Nikon focusing rail, and the Nikon PB-4 bellows for macro. I purchased one, and it is on the way. I suppose I could decrease the step increment by replacing the Leica BF200 fine adjustment knob with a larger (> 5cm) one - or am I not thinking about this right? Anyway, I don't know if it is capable of doing 1/1000th of a mm slices, but maybe it doesn't have to? I do have the oil for the 100x objective. I assume a cover glass is used for that, and the oil creates a surface tension droplet between the front element of the objective, and the cover glass? However, I just started looking at how to collect my own critters to photograph, and I got some synthetic Balsam from Canada. Was there some balsam kerfuffle? I would think Canada would be swimming in the stuff, but you can't buy it anymore? What happened?
Jim