Dr Klaus Schmitt
Well-known member
Well, there is a special story behind this lens I am going to present here. I got a lens donated for my work by a forum member I am part of, a very kind and actually very touching story, as I never would have expected that...
So now on to this f4.3/172mm lens, which has a built in blue (?) filter in it [these are not my images, but from the donating member here...]
Now these are some quick test shots hand-holding filters in front of the lens: the blue image is what seemingly it was made for (projecting images to a fluorescent screen I'm guessing), then I took that internal filter out and did an UV shot using a 365nm UV LED (quite sharp image) plus using the Baader-U filter and then a visible light image with suitable VIS-filter (which shows the lens was not computed for that) - all shot wide open at approx f4.
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Here now the transmission of that lens: The RED line is the filter alone, the GREEN the lens alone, the BLUE as it came assembled with filter inside. Most likely it was designed to project images onto a fluorescent screen. That built in short pass filter makes me believe that. It is not really UV, but short wave blue, enough to stimulate visible fluorescence.
Again, I am very thankful for the thoughts and donating this lens to me! The one who this goes to knows...
So now on to this f4.3/172mm lens, which has a built in blue (?) filter in it [these are not my images, but from the donating member here...]
Now these are some quick test shots hand-holding filters in front of the lens: the blue image is what seemingly it was made for (projecting images to a fluorescent screen I'm guessing), then I took that internal filter out and did an UV shot using a 365nm UV LED (quite sharp image) plus using the Baader-U filter and then a visible light image with suitable VIS-filter (which shows the lens was not computed for that) - all shot wide open at approx f4.
#1
#2
#3
Here now the transmission of that lens: The RED line is the filter alone, the GREEN the lens alone, the BLUE as it came assembled with filter inside. Most likely it was designed to project images onto a fluorescent screen. That built in short pass filter makes me believe that. It is not really UV, but short wave blue, enough to stimulate visible fluorescence.
Again, I am very thankful for the thoughts and donating this lens to me! The one who this goes to knows...