Archived posting to the Leica Users Group, 2001/11/15
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]John, I had not noticed it in Osterloh's book before, but I now looked it up (p. 43, German edition) and sure enough, he says that, in effect, the actual maximum aperture of a Noctilux is not f1 but somewhere around f1.1-f1.2. I do not own one of those beasts anymore, but when I did, I never noticed the effect, and I cannot produce it with my Summilux. perhaps Ray should have his camera/lens combo checked after all. Nathan John Collier wrote: > It is normal. The inherent vignetting of any optical system wide open causes > this effect. It is most noticeable with the Noctilux. See Osterloh's Leica M > book for a well illustrated explanation. > > John Collier > > PS: Try your local library for the book. I might be persuaded to scan the > relevant sections out of my copy if you cannot locate it. > > > From: Ray Moth <ray_moth@yahoo.com> > > > > I've just noticed a peculiarity in the behaviour of the light meter in > > my M6 TTL, using a 50mm Summilux-M lens. If I adjust the aperture from > > f/1.4 to f/2 or vice versa, the meter doesn't register any change, > > whereas a change in shutter speed does register. > > > > For example, if the meter indicates that f/1.4 at 1/500 sec. will give > > the correct exposure, then I would expect f/2 at 1/250 sec. would give > > the same indication but it doesn't; it shows over-exposure, as if I'd > > selected the slower shutter speed but left the lens aperture at f/1.4. > > Conversely, if I started at f/2 and 1/250, a change to f/1.4 and 1/500 > > would indicate an under-exposure. The lens aperture selector seems to > > function properly. Has anyone else experienced this problem? > > > > -- > To unsubscribe, see http://mejac.palo-alto.ca.us/leica-users/unsub.html - -- Nathan Wajsman Herrliberg (ZH), Switzerland e-mail: wajsman@webshuttle.ch Photo-A-Week: http://www.wajsman.com/indexpaw.htm General photo site: http://www.wajsman.com/index.htm - -- To unsubscribe, see http://mejac.palo-alto.ca.us/leica-users/unsub.html