Can someone tell me the difference between these two Nikon apos?

[mrlowndes]

Can anyone tell me the difference between these two nikon 20X apo objectives listed on ebay, other than the difference in NA? One black, the other silver. Which one is the older one?

https://www.ebay.com/itm/Nikon-Plan-APO ... Swj8he~8EN

https://www.ebay.com/itm/GENUINE-Nikon- ... SwXeJe6M0a

Thanks,

[PeteM]

The silver one is fairly old - I believe before the "chrome free" era. Still likely of excellent quality but may require some compensation in the eyepiece.

The "genuine" black painted one isn't one I'm familiar with as a Nikon.

[RobertOToole]

Can anyone tell me the difference between these two nikon 20X apo objectives listed on ebay, other than the difference in NA? One black, the other silver. Which one is the older one?

https://www.ebay.com/itm/Nikon-Plan-APO ... Swj8he~8EN

https://www.ebay.com/itm/GENUINE-Nikon- ... SwXeJe6M0a

Thanks,

Silver unit is older.

Don't recognize the black 20x, the current 20x is similar specs but isn't black:

This is the current Nikon Objective PDF:

https://www.nikon.com/products/microsco ... mphk-2.pdf

Another Nikon PDF with more objectives:

https://www.nikon.com/products/microsco ... muzh-6.pdf

[abednego1995]

That silver PA20x is a CF series objective in production from 1976 to 1985. Pretty old, but good objective nonetheless. The black PA20x is a very recent finite objective made for a discrete slide scanner around 2013. It wasn't sold publicly and is rare. Excellent properties, but it lacks the spring safety so be careful not to run it into a slide.

Cheers,
John

[mrlowndes]

Silver unit is older.

Don't recognize the black 20x, the current 20x is similar specs but isn't black:

This is the current Nikon Objective PDF:

https://www.nikon.com/products/microsco ... mphk-2.pdf

Another Nikon PDF with more objectives:

https://www.nikon.com/products/microsco ... muzh-6.pdf

Thanks but these two documents reference infinity objectives. I'm looking for 160TL objectives

[mrlowndes]

That silver PA20x is a CF series objective in production from 1976 to 1985. Pretty old, but good objective nonetheless. The black PA20x is a very recent finite objective made for a discrete slide scanner around 2013. It wasn't sold publicly and is rare. Excellent properties, but it lacks the spring safety so be careful not to run it into a slide.

Cheers,
John

Thanks! I don't suppose you can tell me the difference btween these three 20X plan apo objectives?

https://www.ebay.com/itm/NIKON-objectiv ... SwQKtek3pG

https://www.ebay.com/itm/Nikon-Plan-APO ... Swj8he~8EN

https://www.ebay.com/itm/Nikon-20x-0-75 ... 4148776818

[Scarodactyl]

The Nikon CF series lasted for like 20 years, from the 70s into the 90s. There were a few style refreshes between the biophot and the labophot 2. They probably perform similarly, though a newer one (with the black paint) might be marginally better in some way, but it might also be a little less robustly built given shifts in microscope build philosophy over that period. That probably doesn't matter for our kind of work though because we treat objectives nice, so if it's good it's good.

[Chris S.]

Thanks! I don't suppose you can tell me the difference btween these three 20X plan apo objectives?

(snip)

https://www.ebay.com/itm/Nikon-20x-0-75 ... 4148776818

I can't speak to the other objectives listed, but this one is of the well-known N-Plan series, as pictured on page 11 and specified on page 14 of this brochure of finite Nikon CF Lenses.

I have a number of objectives from this series, though not the 20/0.75 apo, and they are quite good. The seller, curt3456, is a member of this forum from whom I've purchased happily at least half a dozen times. If I were in the market, this is the objective I'd purchase, as it is much closer to a known quantity (for me, at least). Do note that the working distance on this objective is 0.64mm--fine on a microscope, but not suitable for macro.

--Chris S.

[mrlowndes]

Thanks! I don't suppose you can tell me the difference btween these three 20X plan apo objectives?

(snip)

https://www.ebay.com/itm/Nikon-20x-0-75 ... 4148776818

I can't speak to the other objectives listed, but this one is of the well-known N-Plan series, as pictured on page 11 and specified on page 14 of this brochure of finite Nikon CF Lenses.

I have a number of objectives from this series, though not the 20/0.75 apo, and they are quite good. The seller, curt3456, is a member of this forum from whom I've purchased happily at least half a dozen times. If I were in the market, this is the objective I'd purchase, as it is much closer to a known quantity (for me, at least). Do note that the working distance on this objective is 0.64mm--fine on a microscope, but not suitable for macro.

--Chris S.

Thanks. I bought my optiphot 7 years ago and sold all its phase contrast components and I am only just now getting round to setting it up for good D/F photography. I'm really just after the best optics I can find for 160TL. Which objectives were the best from the 160TL era from Nikon? There are so many versions of each lens it's quite overwhelming, which is why I kind of gave up 7 years ago

[Scarodactyl]

They weren't making superapos (VC) back then as far as I know so apo is as apo as it's going to get. They're cheap for no good reason, they should be excellent.

The biggest thing for fiddly image quality is setting your microscope head up for direct projection if you are using a trinocular head. In my own brief tests the photo eyepieces seemed to introduce a bit of their own CA, plus they crop the image a lot.

[mrlowndes]

They weren't making superapos (VC) back then as far as I know so apo is as apo as it's going to get. They're cheap for no good reason, they should be excellent.

The biggest thing for fiddly image quality is setting your microscope head up for direct projection if you are using a trinocular head. In my own brief tests the photo eyepieces seemed to introduce a bit of their own CA, plus they crop the image a lot.

Tell me more about direct projection. I have a 2.5X photo eyepiece for photos. Is there another way?

[Scarodactyl]

Higher end nikon objectives from the finite era needed to be able to cover ultra widefield eyepieces with a field number of 26.5mm, so they tend to cover aps-c pretty well. A 2.5x eyepiece by contrast will have a field number around 20mm (someone probably has the right number on hand) and in my own testing they can add an alarming amount of CA. Depending on which head you have it can be easy to remove the photo tube and put your camera sensor down directly on that intermediate image.

[mrlowndes]

Higher end nikon objectives from the finite era needed to be able to cover ultra widefield eyepieces with a field number of 26.5mm, so they tend to cover aps-c pretty well. A 2.5x eyepiece by contrast will have a field number around 20mm (someone probably has the right number on hand) and in my own testing they can add an alarming amount of CA. Depending on which head you have it can be easy to remove the photo tube and put your camera sensor down directly on that intermediate image.

Oh, well that wouldn't work for me because I'm using full frame so it won't cover anyway

[Scarodactyl]

You might find that you get better results anyway even with necessary cropping, though my copy of the 2.5x pl eyepiece may have been particularly bad. Some of the heads (particularly the UW head) also establish an area of infinity focus within themselves, so you could actually replace the ~105mm tube lens in the photo tube with one of a longer focal length and get full frame coverage without the photo eyepiece cropping that way.

[mrlowndes]

You might find that you get better results anyway even with necessary cropping, though my copy of the 2.5x pl eyepiece may have been particularly bad. Some of the heads (particularly the UW head) also establish an area of infinity focus within themselves, so you could actually replace the ~105mm tube lens in the photo tube with one of a longer focal length and get full frame coverage without the photo eyepiece cropping that way.

I have the F head. When I rotate the oculars to the left, I get a direct transmission to the photo eyepiece. I have seen adaptors that will replace the entire ocular head with a photo tube and the camera, but I guess you still need the photo eye piece to relay the image?