Hi, I has been thinking, PUMA microscope could be very useful for what I want to do, when we reads the docs there is how need to be the objetive:
RMS thread
Conjugate focal distance of 195 mm
Parfocal length of 45 mm
160mm
I look on several places, and I was not able to get all the info like in:
Even looking on the oficial pages, I’m not able to found all the info, usually I’m only able to know it is 160mm… the other info seems pretty hard to know, is not even printed on the objetives… or all the 160mm has that properties?
Most objectives from the major microscope manufacturers (Zeiss, Olympus and Leica/Leitz) should be OK provided they are not infinity types and not from antique scopes (like the Watson Bactil) or scopes intended for kids. Those latter two categories are the ones that tend to have non-RMS standard features like conjugate focal length of 185 mm instead of the more modern standard of 195. However, you are right to try to be sure for a specific objective before buying.
All objectives sold on the Optarc.co.uk website are compatible and you can find similar ones on AliExpress and eBay. You can also get them from Edmund Optics and Thorlabs although they tend to be more expensive but they do give more info on their site and sales staff might be more knowledgeable in answering your specific questions to them.
I suppose the thing to be wary of is when you actually see the term ‘185’ in the description you know that is not for you.
In case you need a very specific objective - like the one you show in this post - the best thing to do is ask the seller (or they tell you it is RMS thread and conjugate focal distance 195 and it turns out not to be you might have a case to return the item or get a refund under ‘not as described’ clause) or search the web for info on this model - you might find an old Nikon objective manual on some legacy website or the WayBackMachine.
I have no Nikon microscopes and no experience with Nikon other than using some of their modern infinity scopes at work years ago - so I can’t say if this particular objective you link to is suitable or not. Perhaps someone else on this forum can comment on that.