Author Topic: Using an older Quartz Fluoride Condensor as a taking lens  (Read 337 times)

Dr Klaus Schmitt

  • NG Member
  • *
  • Posts: 825
Using an older Quartz Fluoride Condensor as a taking lens
« on: December 27, 2018, 15:54:35 »
A while ago, on my search for affordable lenses for reflected UV photography, I discovered in an older UV-VIS spectrometer system some seemingly useful Quartz Fluoride Lens system (QFC) of approximately f3.2 / 81mm. It had to be modified to convince it to work with a camera, and also a variable aperture had to be added, but I succeeded finally to get it to work on a mft camera system.

So today a comparision between my "work horse" UV-Nikkor f4.5/105mm (top) and this QFC f3.2/81mm (botttom):





Both images are a Quadriptych of VIS, reflected UV, sim. Butterfly and Bee vision (left to right, top to bottom)

Both lenses differ in focal length, 105mm for the UV-Nikkor vs 81mm for the Quartz Fluoride Condensor lens, and lens speed f4.5 vs f3.2 but other than that they are quite comparable: there is hardly any focus shift, just sharpness and contrast is higher with the rather expensive UV-Nikkor lens compared to the Quartz Fluoride Condensor lens, quite as expected. Other than that this old lens does very well, but it only covers mft sensor format, possibly APS-C (with another modification).
formerly known as kds315

Dr Klaus Schmitt

  • NG Member
  • *
  • Posts: 825
Re: Using an older Quartz Fluoride Condensor as a taking lens
« Reply #1 on: December 29, 2018, 12:45:39 »
It is always difficult to spot the differences between the visible and the ultraviolet image. Hence a few years ago I have developed a method to show a differential image VIS-UV which tuned out in such a way that I call those "psychedelic" due to it colors...

But see for yourself, first the normal visible image, then the UV image, then the differential...







So those light blue areas denote high UV reflection...but I'm sure you saw that already ;-)
formerly known as kds315