MicrobeHunter.com Microscopy Forum

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:





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.

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



and the Optem


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!

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.

I'll try to snap one up if I see one on the cheap.

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

MichaelG.