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UltravioletPhotography

Baader U and two lenses with different UV-bandwidth


ulf

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Lately I got two Focotar 50/4.5 lenses.

One hade a very good UV-performance, the other not.

See the red and green graphs in post #22 here:

http://www.ultraviol...ce/page__st__20

 

Those lenses opened for an interesting spectrographic comparison.

What happens when the transmission is combined with one of our most common UV-pass filter Baader U?

 

The measurement of my Baader U below is reasonably correct both for transmission and wavelengths.

That I cannot achieve with lenses in my measurement setup.

Instead I tried to match the long wave slopes of the lens-filter combinations to the filters spectrogram.

Because of this the Lens-filter transmissions are showed a bit too high in amplitude.

 

The result:

 

post-150-0-92366100-1515951404.jpg

 

The difference is interesting, but in then our camera sensors also lose their sensitivity in the short wavelength end, making the difference a little bit less important.

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