Dangers of UV : yellow or yellow-green filter enough?

[charjohncarter]

John, as Roger stated, and I mentioned- "most" any filter that you use, yellow, green, polarizer, etc, also cuts UV.

On a humorous note, I sent a spare Quartz lens and filter that cut visible light and passed UV to a researcher in Germany. They are harder to find than filters that work with Infrared. i would not send him my Calcium Fluorite lens. I like to use that one.

Does that Calcium Fluorite lens give you something similar to the Leica glow? I'd like to see a B&W done with that one. Thanks, for all the info, my Physics is from 1963 so much has changed, especially in optics.

 

[Sonnar Brian]

The Calcium Fluorite lens is color corrected from deep UV to well into the Infrared. I use it mostly for color, need to post some scans with it. Very rich, deep color and interesting Bokeh. I will have to try it for monochrome, where the resolution will be high due to the high color correction. Color dispersion is minimal.

 

[charjohncarter]

Sorry, I know nothing about Calcium Fluorite lenses. I guess I'm of the beam with B&W performance. I still would like to see how it performs with color. Who makes these lenses?

 

[Freakscene]

Lenses for UV photography are quartz crystal or fluorite. The UV Nikkor:
http://www.cameraquest.com/NFUV104.htm
has all fluorite lenses. It is very rare.

You can also buy a very well corrected lens that transmits UV from Coastal Optics, now part of Jenoptik in 60mm (corrected from UV to IR):
http://www.jenoptik-inc.com/standard-products/uv-vis-nir-60mm-slr-lens-mainmenu-155.html
or 105mm (corrected for UV):
http://www.jenoptik-inc.com/standard-products/uv-vis-105mm-slr-lens-mainmenu-40.html

I have used one of the 60 mm lenses and they are amazing for colour photography - and a UV filter actually makes a difference.

Marty

Marty

 

[Sonnar Brian]

The lens that I have is made by Pentax, in M42 mount. I like to use it on an Argus/Cosina STL1000 and a Fujica ST-801.

Prices seem to have gone up....

 

[charjohncarter]

Thanks, Marty and Brian.

 

[hlockwood]

Actually, glass itself is a pretty good UV filter. Not much gets through the lens.

Correct. But the UV transmission spectrum of optical glass (obviously) depends greatly on the composition. If we knew the glass type in our lenses or filters we could answer this question more quantitatively by consulting a (very extensive) table by Schott:

http://www.us.schott.com/advanced_optics/english/download/datasheet_all_us.pdf

A simpler look at the absorption spectrum of various photo filters can be found here:

http://photo.net/photo/edscott/cf000010.htm

Best bet, as someone already suggested, is to do a direct comparison, exposures with and without a UV filter.

Harry

 

[maddoc]

Norwegian nature photographer Bjørn Rørslett has some very nice color UV photos on his web-page.

UV filter are good for physical protection and to filter UV light at high altitude but otherwise, a skylight 1B (color) or yellow filter (BW) will do better.