Archived posting to the Leica Users Group, 2000/07/21
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search][Ok, I give up on AOL] Do we all need an ND8x (0.9) filter?! This is a problem I was thinking about when I started shooting the hell out of my 35/2 Summicron last week. People always rail about using a skylight or UV because it "wrecks the optical system." I think there is one filter that actually improves the optical output. Don't we all need an ND8x? If Leica lenses like the Summicron are diffraction-limited at f/8 and smaller (per Erwin Puts), don't we all need an ND8x filter with most lenses? On a sunny day, the exposure should be roughly (with ISO 100/125 film - negative): f/16 and 1/125 To get to f/5.6 we need to increase the shutter speed to 1/1000. This doesn't really work with the older cameras (like screwmounts) unless they are consistently tuned-up. (Query: so why does Leica make 35/2 and 50/2 SM lenses, unless they anticipate a faster shutter somewhere - or is it a marketing gimmick - or anticipated to be "shared" with an M6?) But suppose we start using 400 film (like, say, Tri-X or TMY. Probably better to think color for the resolution) Then we need 1/4000 sec. But if we're shooting portraits on 400NC with an Elmarit, Nikkor, Hexanon or Jupiter 85/90, we want f/2.8 or 4 Then we need 1/8000 sec or 1/16000 sec, unless we bring that down with a 0.9 to get 1/1000 or 1/2000. ------------------------------------------------------------------------ Dante Stella http://www-personal.umich.edu/~dante