Archived posting to the Leica Users Group, 2000/10/28
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Almost 4 weeks ago I reported about flare in my M4-P, a flare with a very sharp boundary 1.7 mm from the bottom of the negative (top of the image). As I indicated in a second message, I could show a light leak between the flange of the lens and the mount on the camera. My lens (a 35/2 latest non ASPH) was sent to Odin, the Dutch importer and they reported that nothing was wrong with the lens. They were right, since mounted on an M6, there is no light leak, only on two M4-P bodies. After carefully looking, I found that there are places between lens and body where a gap of about 0.01 mm exists. I could show that by putting the corner of a cigarette paper between lens and body and still being able to pull it away after mounting of the lens. In other places it was not possible to pull it away without tearing it. Different lenses showed different locations of the gap, so it is a very subtle interplay between the flange of the lens and the mount of the body. Slight imperfections and tension in the metal due to the springs that hold the lens in place may cause the differences. Anyway, it means that with very strong side lights, which is when I got the veiling flare, light enters through the gap and is not stopped by a ring behing the mount, as is the case in the M6 body. Ofcourse my first idea was to put an M6 ring in the M4-P body, but the frame of the M6 is adapted to be able to mount the ring. Therefore I cut a horseshoe shaped profile from the black non shiny plastic cover of a videotape, including part of a corner to mount it in the bottom of the body and carefully sculpting the shape to allow for the movements of the focus crank. The plastic part now covers the four corners through which light can leak of the mount. The plastic shape was mounted in the bottom by means of two-sided tape, to avoid permanent changes to the M4-P. This afternoon I shot a testroll under extreme conditions, with a 50 Watt halogen lamp at 10 cm. from the side of the camera and shooting at a dark scene, exposing correctly for the scene: Result: no flaring in 36 testslides with sidelight coming from all kinds of directions. Now it may be possible that the mount of the M4-P is worn slightly, or that the springs have lost a bit of tension, but my M4-P has been used very little so that is not very likely. Probably this problem occurs more often without a correct diagnosis. Last time I posted this issue, several of you mentioned the same kind of flaring (with an unaffected band), so perhaps I have a solution for you too. If so, let me know and I can e-mail the plastic shape I found after 10 testversions, that fits, does not interfere with the mount and the focus crank, and stops the light leak. I'm glad I don't have to buy an M6 to take care of the problem, because I'm really happy with my hand-held spotmeter and my M4-P. The lightmeter of the M6 would only be a waste on me. Hope this is of use, Bert Otten