Different Nikon 20/0.75 160 Plan Apos

[karhukainen]

I bought a Nikon 20x Plan Apo on Ebay, and the listing had images of a Nikon CFN 20x Plan Apo, the one with metal coloured barrel and two knurled rings. However, I received another objective instead (experiencing deja vu as apparently this keeps happening to me). I haven't tested the objective yet, but it looks at least dirty. When I opened the case, three "rings" fell off. What are they? I'm I right in guessing this objective is a lesser version of what I thought I was buying?

[Phill Brown]

Item does not match images in the listing.
Seller pays return.
Full refund.
Seller may offer a partial refund.
You don't have to accept.
Looks like a $20 Chinese objective but I'm wrong most of the time.

[karhukainen]

Item does not match images in the listing.
Seller pays return.
Full refund.
Seller may offer a partial refund.
You don't have to accept.

Yeah, I know this but would like to know what this objective is. I remember hearing about Chinese cheaper objectives made for Nikon and was thinking maybe this is one of those.

[Scarodactyl]

From what I understand this is a newer production run post-finite era that Nikon did for some OEM usage. Should be great if in good condition.

[zzffnn]

Those metal rings are shim rings for making objectives parfocal. Those microscopists who cares to use them generally know what they are doing. If the original user cares to use those rings and was happy with performance of the objective, then the objective may be a good one (if not damaged afterwards).

An microscope objective lens can look like trash outside but produces beautiful images, or looks pristine outside but produces trashy images (due to internal misalignment for example). You just have to test it yourself.

[Phill Brown]

Would depend if you paid extra for something it's not.

[karhukainen]

From what I understand this is a newer production run post-finite era that Nikon did for some OEM usage. Should be great if in good condition.

Can anyone else confirm this?

[BramHuntingNematodes]

I don't think Nikon ever made a cheap plan apo.

[PeteM]

From what I understand this is a newer production run post-finite era that Nikon did for some OEM usage. Should be great if in good condition.

Can anyone else confirm this?

I think your best bet at confirmation would be to image something like a diatom or a micrometer slide and compare the resolution and chromatic aberrations with a Nikon plan achromat.

Stephen, who gave the original answer, is almost always right. Like Phill, and not knowing any better, I also thought this was some sort of Chinese make-believe plan apo when first seeing them in eBay. That's probably not right. The objective may be made in China, sourced by Nikon. But even the most rapacious makers of fakes try to copy the real thing.

[Phill Brown]

All good points.
The only image I found of this objective is eBay.
Which series is it from?
Should be able to find matching plan apo set?

[Scarodactyl]

They have both contemporary 4x and 20x apos. I don't have firsthand knowledge of their oem usage but I've read it a few places and IMO it makes more sense than a Chinese company making 160mm apos and only ever selling them as Nikons.
This is presumably a reissue of the CFN apos since they have the appropriate NAs, though maybe with an updated design.

[viktor j nilsson]

Same WD too.

[Scarodactyl]

Personally I was pretty tempted when there was a listing for these kind of cheap, and I don't even have a finite Nikon. This is the one I'd want of the available finite 20xes.

[Midnight9999]

How your situation with this objective ended? How was the image? Is this objective spring loaded?

[karhukainen]

How your situation with this objective ended? How was the image? Is this objective spring loaded?

I sent this message already via pm, but decided to add it here as well in case someone else is interested:

I've been pretty happy with the objective. It seems to perform better than the slightly damaged Fluor 20x that I previously used. It's not spring loaded as far as I can tell. Of course it might be stuck, but my copy appears to be in good condition, so I don't believe that's the case.