Archived posting to the Leica Users Group, 2005/09/27
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Nice reply: I learnt something more: another problem to think about ;-) On 28/09/2005, at 5:06 AM, John Black wrote: > > >>> >>> The film is showing streaks on bright areas, although they are >>> intermitent. My guess is that it is the curtain..I don't know. After >>> all >>> I will have to send the camera for check-up. >>> >>> Here it is.... >>> >>> http://www.photo.net/photodb/photo?photo_id=3760181 >>> >>> > > I think I know exactly what that is... Had the problem with LTM > cameras > myself. I'll bet the shutter speed was high, perhaps 1/500 or 1/1000. > If > you will notice, the fabric of the curtains is wrapped around the end > of the > blind edges and sewn, unlike M camera blind edges which have metal > "lips". > When set to very high speeds, the shutter merely creates a very narrow > "slit" between the first and second curtain that travels across the > film > plane. When shutters get old and need readjustment, the slit is too > small > and the texture of the fabric creates "bumps" in the slit that double > or > halve the effective speed by narrowing the gap. Normally this is not a > problem as the slit is wide enough that the fabric texture only > accounts for > maybe 10-20% variation, not 50%. The M shutter corrected this by > providing > a sharp, smooth metal edge for the traveling slit. > > Get a good CLA and it will go away. > > JB > > > > > _______________________________________________ > Leica Users Group. > See http://leica-users.org/mailman/listinfo/lug for more information > > Alastair