Leitz Periplan 10X 170mm Red Dot Troubles!

[Element 56]

I was so happy to finally find a 10x Periplan for my Orthoplan that I didn't mind the $100 price tag! Although it looked good in the photos I was very disappointed when I opened the package. The optics are very dirty which might clean up okay but there's some scratches that I'm not thrilled about. Also the upper body that holds the optics has some machine work that doesn't look factory to me. In fact I'm sure it was done by someone trying to dial it in to their optical system. Although shown in the eBay listing I didn't catch it until it was in hand. It's also full of lint on the inside which again I think I can clean up.

Anyway I'm pretty much just asking for opinions. Should I take the time to clean it up both optically and the machine work or should I send it back and keep looking? It's really been difficult to find a high point for a 170mm system let alone a red dot. However, I have read that optically this eyepiece needs to be in excellent condition to perform well and this one is not. Alternatively I could buy a 160mm tube length for less than half the price but I'm not sure how well it would work in a 170mm system?

Your thoughts on this matter are greatly appreciated.

Note, for the record I do not believe the seller did anything wrong nor was he trying to deceive.

Thank You,
Kirby

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[Scarodactyl]

I'd return it.

[Element 56]

I'd return it.

Yes indeed, if I can use a 160mm eyepiece that's what I'm going to do.

Has anyone tried a Periplan for 160TL with 170TL objectives? I'm guessing it's just a matter of lowering the eyepiece in the photo tube? Also is there a specific field number I should look for?

Thanks
Kirby

[Scarodactyl]

As far as I could tell for 160mm the one I set up used exactly the same eyepiece as you would for viewing.
The eyepiece holder for 170mm is taller as you would expect (I'd guess about 10mm taller, though I haven't measured it).
I have tried the 160mm/170mm combination but not with a high quality objective. Results were perfectly within the context of the testing though--I think there is a difference in corrections though from what I've read.

[Element 56]

Thank you for sharing this.

I did pop the eyepiece I bought in my photo tube but it's so dirty it wasn't worth taking any photos. I don't want to try cleaning it since I'll likely be returning it.

Another seller offered me a set of Periplan 10x 18 highpoints for $30 that I might try. I'm thinking that 18mm would be more than fine in a photo tube although this is all new to me. I also wonder about those Leitz 4x projection eyepieces but haven't found much information on them.

Anyway I'm also thinking about simply upgrading the 170TL optics to 160mm! I just tested a cheap Leitz 160mm 100x/1.25 oel objective and really liked it. I need to look at it closer but there's no other marks on it so at the moment I don't really know what it is!

Kirby

[Scarodactyl]

The one I used was an 18, it worked well with a 40mm pancake lens onto aps c.

[Element 56]

The one I used was an 18, it worked well with a 40mm pancake lens onto aps c.

Regarding the 40mm pancake lens. Is there any advantage or disadvantage to using the 40mm lens instead of the 24mm that's intended for crop sensors? Seems logical to buy the 40mm in case I decide to upgrade to a full frame down the road but I wonder if the performance is the same between them.

Kirby

[apochronaut]

There was that 1976 memorandum. Have you seen that?


According to that memorandum from Leitz, regarding the difference in the usage of ojectives and eyepieces in the new 160mm microscopes, 170mm eyepieces can be used in the 160mm microscopes with a spacer ( presumably 10mm) in order to get the eyepiece diaphragm into the proper plane but the 160mm eyepieces would require a 10mm reduction in the tube length, so they are deemed unacceptable in a 170mm microscope. There is no mention of any difference in corrections of the eyepieces as far as I remember
Search Leitz 160mm memorandum.

[Scarodactyl]

The one I used was an 18, it worked well with a 40mm pancake lens onto aps c.

Regarding the 40mm pancake lens. Is there any advantage or disadvantage to using the 40mm lens instead of the 24mm that's intended for crop sensors? Seems logical to buy the 40mm in case I decide to upgrade to a full frame down the road but I wonder if the performance is the same between them.

Kirby

40mm is correct if you want a well-sized rectangular crop of the FoV. 24mm would probably get you the whole image circle but by necessity with tons of vignetting, which is usually not considered ideal. It wastes a lot of your camera sensor and is usually not the best way to present pictures.
Here is the 40mm lens picture overlaid on a cellphone shot of the entire eyepiece fov:

It could take a slightly shorter lens to get those corners but a known good 40mm is readily available (if a bit pricey).

[MichaelG.]

I’m not sure how relevant this might be ... but it contains some brief technical details, so seems at least worth noting: https://theskysearchers.com/viewtopic.php?t=4108

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and here’s a useful snippet from the Ortholux II manual:
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MichaelG.

[MicroBob]

Hi Kirby,
in my experience scratches on eyepiece lenses can show heavily in the image, especially when used with stronger objectives.
The Leitz 160mm and 170mm objectives were very similar, sometimes identical. The eyepieces were different though: The 170mm eyepieces pick up the intermediate image 18mm down the tube, the 160mm eyepieces 10mm down the tube. This explains why the objectives are so similar at 10mm tube length difference. So it wouldn't help to buy 160mm objectives, you would need the right combination of tube and eyepiece.
Can you shorten the eyepiece tubes by means of the interpupillary distance setting or by hacksawing?

Bob

[Element 56]

[/quote]
It could take a slightly shorter lens to get those corners but a known good 40mm is readily available (if a bit pricey).
[/quote]

That picture is an excellent visual aid! Which 40mm pancake lens do you recommend? I was going to get the Canon EF 40mm f/2.8 STM but maybe that's not the best option.
https://shop.usa.canon.com/shop/en/cata ... m-f-28-stm

There was that 1976 memorandum. Have you seen that?

I have but I forgot about it! I just read it again and it does say you can use the 160mm Objectives on microscopes with 170mm TL. Page 2, question 3, can 160mm objectives be used on microscopes of 170mm tube length? The answer says that on objectives of a magnification of 16:1 or higher the 2mm displacement of the intermediary image has no noticeable affect on image quality. It goes on to say that "it might be worth mentioning in this connection that with binocular tubes which do not have a tube length correction for interpupillary distance, the tube length changes +/-10mm." Fortunately my Orthoplan has mechanical tube length compensation.

I’m not sure how relevant this might be ... but it contains some brief technical details, so seems at least worth noting: https://theskysearchers.com/viewtopic.php?t=4108

Michael thank you for the link I will take a look at it.

Hi Kirby,
in my experience scratches on eyepiece lenses can show heavily in the image, especially when used with stronger objectives.
The Leitz 160mm and 170mm objectives were very similar, sometimes identical. The eyepieces were different though: The 170mm eyepieces pick up the intermediate image 18mm down the tube, the 160mm eyepieces 10mm down the tube. This explains why the objectives are so similar at 10mm tube length difference. So it wouldn't help to buy 160mm objectives, you would need the right combination of tube and eyepiece.
Can you shorten the eyepiece tubes by means of the interpupillary distance setting or by hacksawing?
Bob

Thanks for the information Bob. I think after reading the memorandum I am going to leave my tubes alone for the time being. If I do find it necessary I would seek a second set of binoculars and turn them down on the lathe.

Thank you all for the help. I think I have a much better understanding of what I can and can't do with my photo eyepiece options. I'm going go ahead and order the 160mm eyepiece and try it in my photo tube. I actually think the tube I bought for it is a 160mm tube anyway. It's position is of course adjustable so I think no matter what eyepiece I use, 160 or 170 I should be able to get it in the correct position and be pretty close to the viewing eyepieces. We will see!

Kirby

[Scarodactyl]

It could take a slightly shorter lens to get those corners but a known good 40mm is readily available (if a bit pricey).

That picture is an excellent visual aid! Which 40mm pancake lens do you recommend? I was going to get the Canon EF 40mm f/2.8 STM but maybe that's not the best option.
https://shop.usa.canon.com/shop/en/cata ... m-f-28-stm

I have used the canon one successfully, and experimented with a few cheap surplusshed lenses unsuccessfully (introduced chromatic abbersrions).