Today a comparison between the well known UV-Nikkor 105mm lens and the lesser known Steinheil Cassarit f4.5/105mm enlarger lens. I'm using a patterned Phalaenopsis flower for that comparison and my work horse UV filter, the Baader-U filter. Light source was an UV enhanced Xenon flash as well as a Nichia 365nm UV LED. All shots done at f8.
[click on image to see a larger one; UV-Nikkor is on the left, Steinheil Cassarir is on the right]
UV-Nikkor vs Steinheil 105mm: VIS image using UV/IR Cut filter and Xenon flash:
UV-Nikkor vs Steinheil 105mm: UV image using Baader-U filter (approx. 320-395nm) and Xenon flash:
UV-Nikkor vs Steinheil 105mm: UV image using Baader-U filter (approx. 320-395nm) and UV LED:
That Steinheil lens transmits down to about 330nm and at 365nm has about 65% transmission. It needs refocussing when used for UV and the focus difference VIS-UV is just 1.2%, which the corrected UV-Nikkor lens does not need.
This comparison shows, that the UV-Nikkor 105mm is very hard to beat, but this Steinheil lens does very well, especially when used with an UV LED, considering it being a simple triplet lens. Finding a longer focal length UV-capable lens is a hard thing to do, so that Steinheil seems to be rather useful!
I have written about other Steinheil lenses HERE.
Stay tuned, more will follow on that fascinating subject...
More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos