polyvar photo tube

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SteveG
Posts: 1
Joined: Sat May 15, 2021 6:59 am

polyvar photo tube

#1 Post by SteveG » Sat May 15, 2021 7:11 am

Hi I'm new to the forum but have an issue that I need urgent help with.
I have a lovely polyvar bright field microscope I purchased recently.
I've have on sale and return a specifically made polyvar photo tube that I've attached to a friends Canon 6 MKII camera.
The image quality is excellent but I have spherical aberration ? on all images at various mags.
Through the eye pieces the image is excellent and flat.
I'm assuming the problem lies with the photo tube optics.
Any thoughts would be very welcome.
SteveG
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Microbito
Posts: 5
Joined: Tue May 25, 2021 9:02 pm

Re: polyvar photo tube

#2 Post by Microbito » Tue May 25, 2021 9:06 pm

just posting to read what other users tell you ... good luck!

MichaelG.
Posts: 2901
Joined: Mon Apr 10, 2017 8:24 am
Location: NorthWest England

Re: polyvar photo tube

#3 Post by MichaelG. » Tue May 25, 2021 9:27 pm

Welcome, Steve

... I think you might want to chat with Dan :
https://www.microbehunter.com/microscop ... ar#p103859

My guess is that the optics in your custom photo-tube would be fine on the common breed of ‘scope, but are not flat enough to handle the wide field of the Polyvar.

MichaelG.
Too many 'projects'

Scarodactyl
Posts: 1418
Joined: Sat Mar 03, 2018 9:09 pm

Re: polyvar photo tube

#4 Post by Scarodactyl » Tue May 25, 2021 10:18 pm

I didn't respond here since I responded to his identical query over in the amateur microscopy group on facebook, but didn't check back in there.
The adapter he is using is from Best Scientific, who are the US distributor for Optem's camera adapters. Like many other well-known businesses in this space these are probably a one-size-fits-all solution optically and assume a fully corrected image is coming up the photo tube. However the Reichert tube lens is apparently fairly neutral, so corrections probably happen mostly or entirely in the eyepieces. Maybe monkeying around with the distances could get a flatter image, but probably at the cost of some other aberrations.
My instinct would be an afocal approach but I'm not sure of the logistics of getting a massive 28mm FN onto an aps-c camera.

MichaelG.
Posts: 2901
Joined: Mon Apr 10, 2017 8:24 am
Location: NorthWest England

Re: polyvar photo tube

#5 Post by MichaelG. » Tue May 25, 2021 10:52 pm

Scarodactyl wrote:
Tue May 25, 2021 10:18 pm
I didn't respond here since I responded to his identical query over in the amateur microscopy group on facebook, but didn't check back in there.

[…]
Thanks for sharing that
... I don’t use facebook

MichaelG.
Too many 'projects'

Scarodactyl
Posts: 1418
Joined: Sat Mar 03, 2018 9:09 pm

Re: polyvar photo tube

#6 Post by Scarodactyl » Tue May 25, 2021 11:48 pm

Facebook is, in my opinion, worse than a forum in just about every way for discussing this sort of thing. But that's where a lot of people are so them's the breaks I guess.

apochronaut
Posts: 4321
Joined: Fri May 15, 2015 12:15 am

Re: polyvar photo tube

#7 Post by apochronaut » Wed May 26, 2021 1:14 am

Wow. In Canada, cigarette packages have to have 1/2 of the box present a negative image of smoking. So , there are pictures of lip cancers, black lungs etc. That image could be used on booze packaging. This is what your liver looks like on Gin. When I try to focus on it, my brain hurts.

Michael G's link is a good idea, since Dan is seasoned on a Polyvar. Also wporter has a Univar, which uses the same objectives and more than likely uses the same photo relay lens.
I use the same objectives in a Diastar . The telan lens in that system provides some corrections but there are further tweaks in the eyepieces, so the photo relay lens does have to provide those same corrections but more than that, it must be in the correct location. That might be where the spherical aberration is coming from.

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