Another interesting microscope objective my friend loaned to me is the Leitz 20x quartz objective. This microscope objective, however is an infinity corrected objective which needs to be stacked with another lens in order to achieve sharp focus. Hence I stacked this together with my Coastal Optics 60mm F4 APO lens to maximise the UV-transmission.As I wanted to test the UV-imaging capabilities of this setup, I mounted the Leitz 20x onto my 42mm-RMS adapter, 52-42mm step down ring, 49-52mm step up ring mounted onto my 49mm Baader U. This was attached to the Coastal Optics 60mm via the Xume magnetic adapter. I used my Olympus FL-36R flash to be the UV light source and my Olympus E-M5 as the camera.
1) Can it fill the full sensor of the Micro 4/3rds?
Ans: No. It only lights the center of the sensor. See below.
2) Does it transmit UV well and is it sharp?
Ans: It does transmit deep into UV (limited by the Coastal Optics transmission), but it is not corrected for UV and hence is not very sharp.
But it is capable of doing extreme macro in UV and catching the fine details in the UV pattern.
I did mount this lens on its own with the 42mm-RMS adapter and a focusing helicoid. While it did fill the entire screen on my Micro 4/3rds sensor without showing any black corners, the image produced was not as sharp (even with narrow bandwidth light source).
While the Leitz 20x quartz microscope objective can pass deep into UV, it is an infinity corrected objective and will require another lens for it to achieve sharp focus. It is not colour corrected for UV and hence will be softer than a lens which is corrected. But it does allow for extreme UV-macro, albeit only covering the center of the Micro 4/3rds sensor (unless you were happy with a softer image in which case it can be used without stacking onto another lens).