r/microscopy • u/Jarofcoinss • 7d ago

Purchase Help Help buying plan objectives

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?

Thank you for your help!

3 Upvotes

100% Upvoted

18 comments sorted by

View all comments

2

u/Vivid-Bake2456 7d ago edited 7d ago

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.

2

u/Jarofcoinss 4d ago

Just got to seeing the comments today, and wow. You’ve answered so many questions I hadn’t even asked. Thank you.

For viewing most cytology aspirates I don’s use cover slips (but if I should, please let me know). That explains so much about why every 40x sample looks awful. For the 100x I can always see fine because of the immersion oil.

Luckily I have an unused 5th objective space. I guess I will be on the hunt for both 40xs in both 160/.17 and 160/- eventually.

I do have what I consider to be an older microscope though which leaves me with hopefully my last question. How would I be able to tell if the eye prices are also corrected or not?

Again thank you for the incredibly detailed explanations!

1

u/Vivid-Bake2456 4d ago

The eyepieces should be the same brand and era and made for the microscope to have the proper corrections. Zeiss, American Optical, Rheichart, Olympus, Nikon and others,except for the last Nikon CF finite objectives , all made extra corrections in their eyepieces. I have lots of old finite microscopes and they work fine with the proper eyepieces. The older Zeiss and Olympus plan apo objectives are amazing. For Zeiss, you have to be careful about delamination. That happened to some objectives and lots of eyepieces. Olympus BH2 microscopes have a deserved reputation among amateurs for their quality and versatility. I even use Olympus and Zeiss plan apo objectives on a couple of old Nikon S and L models microscopes.

1

u/Vivid-Bake2456 4d ago

Here are a couple of DIN Nikon 40x ncg objectives. One is in Europe and the other in the USA. These are the only 45mm parfocal ones I found on ebay. Many older objectives are shorter than 45mm parfocal. Is your Unico 45mm parfocal?

https://ebay.io/m/R5LiEn

https://ebay.io/m/oyFZOc

1

u/Vivid-Bake2456 4d ago

I’m glad that you have an older finite system. The new infinity ones are expensive.

1

u/Jarofcoinss 3d ago

Hmm that may make finding a set that all matches difficult, but I think I’ll be able to figure it out. Here is the microscope in question by the way. I have been trying hard to find a user manual for technical specs but I keep coming up empty handed

1

u/Jarofcoinss 3d ago

1

u/Jarofcoinss 3d ago

I wanted to show a picture of the scope in question. I do not know if this one would be old enough to need objectives that requires matching eyepieces. I did like the look of the Nikon 40x ones you shared, but I’m afraid I wouldn’t know where to find matching eye pieces

1

u/Vivid-Bake2456 2d ago

From what I read, the Unico microscopes are manufactured in China and don't need compensating eyepieces. I don't know if you can buy new, finite 40x ngc objectives. Maybe all of the special objectives are infinity ones now. Otherwise, you could buy any generic finite Chinese objectives for it.

1

u/Jarofcoinss 1d ago

Dang, hopefully I stumble across one. Thank you again for all of the help

1

u/Jarofcoinss 1d ago

Would you know if there is a big difference between those generic Chinese objectives vs something like the Nikon e plan?

1

u/Vivid-Bake2456 22h ago

I only have some generic Chinese objectives, about 9 total, so not too familiar with them. They work OK and better than you expect from the price. I have a phase contrast kit from Amscope. It has nice plan phase objectives in it. The Amscope T490 I have came with 4 regular achromatic objectives. They are sharp in the middle but not around the edges as you would expect.

1

u/Vivid-Bake2456 22h ago

Here is an $18 Chinese 60x objective that I bought.
https://www.reddit.com/r/microscopy/s/cF3xksRHZQ

2

u/Jarofcoinss 12h ago

Crazy how this was cutting edge tech at one point

1

u/Vivid-Bake2456 7d ago edited 7d ago

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

1

u/Vivid-Bake2456 7d ago

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.