M42 lens on Sony A100 - Noob question

[maninthemaze]

Hi everyone

 

quick question from a beginner - I've recently inherited an ancient (but near-mint) A100 from a relative. My first DSLR and a lot of fun so far. Point is, I've bought a couple of cheap lenses off Ebay, a Minolta AF and a Helios 44-2 (m42 mount) with adapter. Now the thing I've noticed is that when I mount the Helios, the camera takes much longer than usual to start up - about 5 seconds, with a whirring noise all along that seems to come from the lens mount. After that everything (lens and body) works as it's supposed to. Is that normal? Is it the AF screw struggling against the adapter, or what?

The adapter is a cheap, chipped one, also off Ebay, nothing fancy but it seems well made. Am I at risk of wrecking my new toy or just worrying over nothing? Any feedback much appreciated and apologies in advance if there is already a similar topic, I honestly couldn't find it.

[miran]

I used to have an A100 once and a cheap M42 adapter and didn't notice such strange behaviour. It's possible that because you have a chipped adapter the camera thinks there's an AF lens behind it and wants to do something with it. I'm not sure but I think when an A100 (or similar camera) detects a lens it doesn't know about, it wants to turn the AF screw once from one end to the other in order to calibrate the AF system. And because the adapter of course doesn't have that, it takes a few seconds before the camera gives up with this calibration sequence. If there was no chip on the adapter, the camera would simply not know about it and wouldn't try to do anything. But that's just my guess.

[maninthemaze]

Hi Miran, thanks for your reply - it makes sense to me! I asked a friend last night who's been into photography for years (though he doesn't use Sony) and his explanation was more ore less the same. Now the real question is whether that's good for the AF screw in the long run... I guess the sensible thing to do is to get a non-chipped adapter and see what happens then!

[roward]

I ran into this with my a33. Turn off the autofocus when you use manual lenses. There should be a sliding switch on the front of the body.