Archived posting to the Leica Users Group, 2001/08/07
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Dear All, Well, it seems that a problem I reported to the list a month ago, concerning the DoF lever on my R8 getting jammed if I pressed it too far down, is worse than I thought! I did some experimenting, yesterday evening, to see whether lens irises are able to close fully to their smallest aperture if I press the DoF lever only as far as the point of resistance, i.e. not far enough to make it jam. I found that they are sometimes able to close down fully but will often stick before getting to that point, i.e. the spring in the lens is not strong enough to push the aperture control ring in the camera, reliably, to its farthest extent. Worse than that, I found there is also a problem when taking a shot using the shutter button. The aperture to which the lens closes is unpredictable and varies from shot to shot. It seems worse at apertures smaller than f/8. The R8's aperture control ring must be binding and is too stiff to be overcome, reliably, by the spring in the lens. I found that it can be helped (if the shutter speed is long enough, say, 4 seconds) by tweaking the DoF lever several times, which can nudge the aperture control ring a bit and allow the lens to close down to the set aperture. I had the R8 in manual mode, BTW, so automatic aperture selection (as in P and T modes) didn't enter into it. I experimented with four different R lenses and had the same problem with each one, so the camera is definitely to blame. It will have to go back to Leica :-( Olympus OM cameras operate the oppposite way to Leica R, that is, the lens is sprung internally to be fully open until it is forced to close down by a lever (not a ring) in the camera. I would think this design must be mechanically faster and more reliable than the ring arrangement in the R cameras. The way R cameras control the aperture seems odd to me, relying on a fairly weak spring in the lens to move a large aperture control ring. There is very little time for the iris to close down during the shooting cycle and any stiffness or sluggishness in the aperture control mechanism will likely lead to incorrect exposures, at apertures wider than those actually selected (except, of course, when the largest aperture is selected). I'm surprised that more R owners haven't reported aperture control problems. Regards, ===== Ray "The trouble with resisting temptation is you never know when you'll get another chance!" __________________________________________________ Do You Yahoo!? Make international calls for as low as $.04/minute with Yahoo! Messenger http://phonecard.yahoo.com/