Difference between reduction lenses

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BramHuntingNematodes
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Difference between reduction lenses

#1 Post by BramHuntingNematodes » Thu May 13, 2021 12:14 am

I have been using an Omax 0.5x reduction lens for the Pi HQ camera, which has a 1/2.3 sensor. I have been ambivalent about this lens since I got it as although it does allow for some good images at nice resolutions, there is a pretty severe fall-off in quality outside of the center. I switched it out with an Optem 25-70-49 adapter which has a eyepiece-fitting tube on one end and a c-mount on the other and is also nominally a 0.5x reduction factor lens. First is the Omax and second is the Optem:

Image

Image

Hey so maybe not perfect on my strobus x-section but a marked improvement I think. A little more fiddling is in order, but both lenses I was able to get parfocal with the eyepieces.
1942 Bausch and Lomb Series T Dynoptic, Custom Illumination

BramHuntingNematodes
Posts: 1538
Joined: Tue Jan 21, 2020 1:29 am
Location: Georgia, USA

Re: Difference between reduction lenses

#2 Post by BramHuntingNematodes » Thu May 13, 2021 2:18 am

These images might be a bit more illustrative, without the funny COL lighting I inadvertently used above. The Omax first again:
Image


and the Optem
Image

You can find these used for not much more than the Omax new. The Omax lens works pretty good, and especially well if you crop it. On the other hand, I spent a long time finding these odd B&L Planachromats and getting them to work, so I didn't want the reduction lens ruining the effect!
1942 Bausch and Lomb Series T Dynoptic, Custom Illumination

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

Re: Difference between reduction lenses

#3 Post by Scarodactyl » Thu May 13, 2021 2:26 am

Optem is a good name, though I would guess that diagnostic instruments (now spot imaging) woule be even better. Never done a head to head, though, and .5xes or .45xes are usually expensive.
Last edited by Scarodactyl on Thu Apr 14, 2022 4:16 pm, edited 1 time in total.

BramHuntingNematodes
Posts: 1538
Joined: Tue Jan 21, 2020 1:29 am
Location: Georgia, USA

Re: Difference between reduction lenses

#4 Post by BramHuntingNematodes » Thu May 13, 2021 3:06 am

I'll try to snap one up if I see one on the cheap.
1942 Bausch and Lomb Series T Dynoptic, Custom Illumination

MichaelG.
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Location: North Wales

Re: Difference between reduction lenses

#5 Post by MichaelG. » Thu May 13, 2021 7:58 am

Thanks for posting the very informative comparison [your second pair], Bram

MichaelG.
Too many 'projects'

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