Archived posting to the Leica Users Group, 2000/11/16
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Tina et al., I would be very curious to know how much "measurably less" light you get after putting a UV filter on your Noctilux. Theoretically it should be so small that it wouldn't be measurable with an ordinary camera or hand-held light meter. If you have the time to test it, I would be quite curious. I just did a test using my 50mm f0.95 Canon lens. The chrome ring containing the rear element fit perfectly around the flat diffuser of my Minolta Flash meter which reads in 1/10th f stops. I set the lens down on top of the meter (no it didn't touch the back element of the lens) and made measurements with and without a 72mm L37C Nikon UV filter in front of the lens, and there was no difference in the reading. Any difference you might have noticed must have been due to some other factor or was less than 1/10th of an f stop. I also removed the flat diffuser from the meter and had the lens project it's light directly onto the sensor. Still no difference. If by chance a 1A/skytlight filter is put in front of the lens, which has a very slight amber/yellow tint, you will lose about 2/10ths of a stop of light according to my Minolta meter's reading. Anyone else have any thoughts on whether a UV filter cuts out a measurable amount of light? Regards, Rob McElroy Buffalo, NY Tina Manley wrote: > At 05:03 PM 11/16/00 +0000, you wrote: > > >Tina, > >I may be missing something here, but a UV filter cuts light?? OK, some, > >but can you measure it? > >(BTW I have no feelings one way or the other on this issue - it's a > >personal choice, not right/wrong.) > >Nick. > > Just based on my experiments. Put a UV filter in front of the Noctilux and > measure the exposure in very dim light. I get measurably less light. You > can try it with a sensitive light meter, too. > > Tina > > Tina Manley, ASMP > http://www.tinamanley.com