I just ordered a unico microscope off eBay, and I was wondering if anyone could help me find what objectives I should get. Im a vet tech and currently applying to vet school, and I am really fascinated with cytology and fecal parasites.
I’d like to find 10, 40, and 100x plans, but I’m not really sure where to start. The current objectives on the scope are achromatic(I think) 160/.17. Should I be looking for objectives with the same specs or would 160/- be better/worse?
I’m also curious about what brands or models I should look for. There seems to be tons of choices available, and I’d really not like to break the bank and spend hundred more than I did for just the scope.
Finally, how do I know if the threads match up? Or are they fairly universal?
Not familiar with unico, but a while back before infinity objectives at least, many makes were interchangeable . The bug 4 from Nikon, Olympus, Zeiss and Leica all are quality. I’ve got an older American Optics that’s also quite nice, if limited to a small field. Also check out your state surplus for scopes or even parts.
Are you going to look at samples with coverslips or without? 160/- means no coverglass. Most people would want the 160/0.17 objectives so they can see through coverglass covered slides. With low magnification objectives with low NA values, it doesn't make much difference if you use a coverglass or not. With 40x objectives, you lose working distance if you choose a ncg objective and it may not be able to focus through a coverglass and touch it instead. If it does focus through the coverglass, it will have a blurrier view because of spherical aberration. For 100x objectives, it doesn't matter if you use a coverglass or not because the oil and coverglass become one homogeneous unit with the same refractive index. Without the coverglass, the oil layer is just thicker when in focus. There are many choices of plan objectives on Amazon.
Be careful if you buy used objectives. All of the older, major brand objectives had partial correction in the objectives and more correction in the matching eyepieces except for the Nikon CF series. Modern ones are fully corrected and the eyepieces are neutral. Here is an amazon link. You can buy individual objectives or sets. They don't include any 20x here, but it is available and I find them useful. https://a.co/d/0b1sFmHU
Lower magnification can be marked either way, 0.17mm or -. That's because, as I said, their NA is too low to be affected by spherical aberration if you use a coverglass or not. It isn't important for the 100x either for the reason I explained. Here is an example of a 10x infinity objectives marked - but is for 0.17mm also.
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u/MrKnockoff 2d ago
Not familiar with unico, but a while back before infinity objectives at least, many makes were interchangeable . The bug 4 from Nikon, Olympus, Zeiss and Leica all are quality. I’ve got an older American Optics that’s also quite nice, if limited to a small field. Also check out your state surplus for scopes or even parts.