> >Mine MZ5N also works perfectly with KA, KAF, > >KAF2 etc lenses but it sucks with srew mount > >m42 lenses - that is what I said! > > I wonder if this problem can be related to the mechanical > aperture coupling with the K-adapter? >
Surely it can! I own original Pentax m42_to_K mount adaptor. I have made some interesting discovery: I place it into my 5N bajonet and turn it clockwise until it blocks inside (by the little spring). When holding body (without lens atached), I discovered that the adaptor is not fixed in place very tightly - I can turn it manually a little bit more and this makes -0,5EV difference in lightmeter readings. I think this 0,5EV is because such adaptors should move the mechanical aperture lever (in body) to its "zero" position. If not, body "thinks" that the aperture will stop down a bit in the moment of shutter release, so it "corrects" it with longer time of exposure. Well, but it is "only" 0,5EV, so where is the second remaining 0,5EV??? Doing some test on negative (spot and CW) it shows clearily that I should always correct by 1EV to achieve proper exposure with screw mount lenses. I was also metering the same scene with two lenses set on the same diaphragme. The lenses were screw mount Zeiss Tessar 50/2.8 and Pentax SMC-A 50/1.7 both set to 4.0 but diferrence was always 1EV. What the hell is going on??? cheers. ======================= Waldemar Krasowski mailto: [EMAIL PROTECTED] =======================
