Hello,
I am a new participant to this great forum, however, I've been a happy reader of it for at least 10 years (esp. the lenses section). I own and use both MF film cameras (ME, MX and LX, since 1999) and digital K-01 and K30 ones. Having gathered some full-frame AF lenses recently for use on digital bodies, I thought that there is a reason to use these on some AF film body as well, and, therefore, got a MZ-5 for this.
Everything (metering, shutter, operation modes) seems to work in this camera except some strange behavior of the AF. The symptoms are as follows. Focusing may work straight after switching the camera on, but only for 2-3 consequent attempts. Say, you focus: (1) on infinity (focuses fine: a beep and green diamond are there), (2) change to a close distance object, 1-2m (fine again), (3) back on infinity again (fine), then the following focusing attempts fail. What I mean is not incorrect focus but no focusing at all. Half-press shutter: nothing happens, AF motor does not turn. Then, if you turn the focusing ring on the lens manually a bit, it starts to focus OK again, for a few following attempts again. Then stops reacting. Sometimes it is not focusing straight after switching on, too. Seems like partly random behavior. One, for sure, can use it in this semi-automatic mode: turn focus ring by hand, then allow it to AF precisely, but of course, it would be better to get it work as desired.
What have I checked:
- sometimes focus is not OK (no beep and to green diamond) even if the AF works, looks like AF is not complete, perhaps, lacking a few additional fine tuning steps
- contacts (body and lens) are clean
- screw drive coupler protrudes and engages fine, is easy to turn on the body without lens being mounted
- lens AF mechanics is easy to turn when the lens is not on camera
- when the lens is on camera - it's not too difficult to turn manual focusing ring when AF is coupled mechanically with the camera, too (this is what I do to bring AF temporarily alive)
- all lenses behave the same
- batteries are fine, no low battery sign, also there are enough power for the mirror motor and shutter, checked also by connecting external 4xAA batteries, all the same
What it possibly could be? Semi-dead focusing motor (which stuck half-way and then is alive when turned by hand)? Are these normal DC motors with brushes or other type? Or some circuit in the AF controller schematics, e.g. some transistor that provides a voltage to the motor? Any other reason?
I have a spare broken MZ-7 for parts and a reasonable experience with fixing mechanical film cameras of many types, but the amount of electronics and esp. wirings inside these beasts and the service manual (a bit difficult to follow) looks too scary.
If someone have any ideas or experience with similar symptoms or their remedies or have seen detailed instructions online, I would be glad to know very much. Needless to say that sending it to service (which we lack here anyway) would be an unreasonable option.
Thanks in advance,
Jaroslav