Backfocus problem with A100

[hassert]

It's been days I'm browsing forums to try find out if I'm alone having such a problem, so far it seems to be the case with the A100 but common with other cameras (like the Dynax 7D)

Is there anyone out there having the same problem as mine :

I can't get sharp images at distances of about 12-15ft. The focus point is always about 1-2 ft behind the subject I focus on. I tried with a Minolta AF 50mm f/1.4, Sigma 24-70 f/2.8 DF DG, and a Minolta AF 28-85 f/3.5-4.5. Same problem with all of them, much less apparent with the 3rd one because of increased DOF. It makes all images taken with the first two unusable at wide openings.

Also, the problem is worse using the top focus point, and least using the bottom. The center spot is in between. I've taken hundreds of pictures of various objets, with other objects placed behind to see that the front one (that I focus on) is blurred whereas the one behind is very sharp is positioned about 1 1/2 ft. behind when shooting from a distance of 15ft. The problem diminishes gradually as I get closer to the subject.

I had the Sigma lens sent to repair for testing, they changed the electronics inside, no change. I tried another Minolta 50mm f/1.4, same thing.

[Canuck935]

If this is the case you should contact Sony for warranty repair/replacement. I can't say I've had any such problem with my alpha (Minolta 50 f/1.4, Tamron 24-135 f/3.5-5.6, Minolta 70-210 f/4, Minolta 75-300 f/4.5-5.6). BTW how do you like the Sigma 24-70 f/2.8? I am up in arms between that and the Minolta 28-75 f/2.8. Thanks.

[hassert]

The Sigma is heavy and feels good, but compared to the Minolta zoom thefocusing is much, musch slower. With the Minolta it's almost instant. Also, the focusing ring on the Sigma can be moved back and forth to "clutch" the focus, it's got to be kept in the"AF" position otherwise by holding it you act against the body's autofocus motor. It's just that it's easy to accidentally clutch it in.

It must say that most of my experience with it has been testings to see if I can get the focus to be right...

I did send the camera for repair. I'm jealous hearing all is good for you with the same lens as mine! Good for you.

[Canuck935]

Did they say how long repair would take? I would hate to be without a camera for any period of time. Hopefully it will be quick and relatively painless.

Thanks for your review of the Sigma 24-70 f/2.8. I have seen a tamron with a similar design using a ring back and forth for auto and manual focus. With the focus ring and the focusing speed issue I think I will go with the Minolta 28-75 f/2.8. Thank you very much!

[hassert]

No they didn't say - it's been there for a week now, and has just been "assigned to a technician" according to Sony's online repair status. God knows.