Archived posting to the Leica Users Group, 2000/11/17
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]> >O.K., Nick. I tried it again. I am using a Minolta IV F Auto Meter. I've >entered 3200 as the ISO and 1/125 as the time. In room light, without the >UV filter in front of the meter I get an f number of 2.89. With the UV >filter, I get an f number of 2.86. Not much difference, it's true, but >enough to matter when you are taking pictures in the dark! In my dark >hallway, with an ISO of 3200 and 1/30, I get a reading of 1.0 without the >filter and a reading of "under" with the UV filter. > >Tina > >Tina Manley, ASMP >http://www.tinamanley.com > > Tina, thanks! We're getting some actual figures posted on this thread at last! Your results are very interesting and do seem to show a measurable influence of the filter, which I had not expected. However, the issue is still unresolved (for me at least) because others find no effect. For example, in an earlier post, using the same Minolta IVF meter but set at 400 ASA, John Collier stated: >Finally I found a tone that gave me 1 second at f1.0 and 0/10ths >(the meter reads to tenths of a stop). I then held up an old >B+W 39E 010 1x filter (UV not MC)in front of the measuring cell >and hit the button. SAME READING EXACTLY. Despite the 3-stop difference between your meter settings, I wonder if different UV filters have the same transmission factors? But 3 stops!?! Seems crazy, but your results show something interesting is going on! This could run and run if we start worrying about which make lets through what percentage UV, so I'll just say thanks again, and test it for myself with my own stuff. Nick. PS. I'm having trouble with my email software, so if this fails to reach you I'll know by the silence. And if so, maybe I'll post it again later when I've wrestled this thing into submission.