DPlanApo 20 UV oil immersion objective acquired

I acquired this crazy objective for a relatively low price. Sadly, there are a bunch of tradeoffs to use it.

Olympus DPlanApo 20 UV 0.80 Oil objective

This objective should be able to resolve details down to 420nm for green light VS around 745nm for a more traditional 20x objective like the MPlanFL 20x/0.45.

It should also be very good in the UV wavelengths so we probably can use it with 400nm UV light with no issues and then resolve up to around 300nm VS around 600nm with blue 450nm on a MPlanFL 20x/0.45.

Post processed picture taken with the 20x/0.80 and my multiplexed RGB illumination

For comparison, same area of the same chip with a MSPlan 20x/0.46 and a white LED

Tradeoffs

Sadly this lens doesn’t come out without any issues:

• It is intended to use with UV light, and I noticed visible back reflections in the red wavelengths.
  This can be fixed with flat field correction.

• This is a 160mm lens, so you can’t use it on the BH2 with it’s epi illumination or the BX with it’s binocular or trino head. Both use infinity corrected objectives. I had to mod my BH2-MA and to remove the tube lens to use this objective.

• This is not a fully corrected lens. You need the NFK photo eyepiece and even with it, transverse chromatic aberrations are visible. Also the NFK eyepiece is introducing a lot of barrel distortion you have to postprocess.

• It requires small pixels to resolve the high level of details. My 1" 20MP camera barely resolve all of these details.

I was able to get great images with it because of my heavily automated and post processed pipeline. But because all objectives on my main microscope are infinity corrected, I’ll probably don’t use this objective much.

This is a good candidate for a custom build or a secondary microscope with finite conjugate optics tho.