I everyone

I am having focus problems with the A100 , i use the 75-300 lens alot for sports photos and latley it has been having problems locking in a focus it wines and grinds and finally gets focus , however, just as i am about to shoot it loses focus again. I have a brand new 50mm and it has begun to happen with this lens.

can anyone help? thanks

Roundinthird

What AF mode are you using? I did not like AF-A neither AF-C with my slow Sigma lens. I use AF-S, and I also use Spor AF area.
Hope it helps.

yes, I prefer spot AF area as well. Keep in mind it may also cause this problem to happen more as well, because it has less area to select from - make sure its focusing on something fairly contrasty.

I had mixed results with action photography on the a100... Generally, I did get better results with wide area and AF-C compared to spot and AF-A. The problem with spot is the second the subject goes out of spot, the lens will hunt. With wide, it will still use some intelligence to follow the target, even if it's not centered in the frame. At least, that's the theory..

The other thing is with the lighting. If lighting isn't good, you'll loose focus a lot easier, and it will hunt more. Better (faster, f1.4 - 2.8, even f4) lenses help with this, as their default "wide open" setting allows better light for the focusing system to work with... No matter your aperture setting, the camera will always do it's focusing work with it wide open and only step down once you pull the trigger...

The a200 and newer alpha cameras do make improvements in this area, especially the a700, but it's still one of the most difficult things to get good results shooting with "average" lenses.

Just be patient, and practice a lot. It's most likely your conditions or lenses, and not the camera. However, if you are still have a lot of trouble mid-day, good light, with a fast lens, then maybe it's worth borrowing another camera, or having it checked out.