Slow in and out auto focus on Sigma 17-70mm F2.8-4.5 Macro DC

[rgrebby]

I find it very differcult to use the autofocus when it is even slightly dark. Im using a Canon 400D and ive tried every AF setting I can and it doesnt seem to help.

All the camera does is focus in and out, sometimes it stops close to being in focus, I press the button again and it goes all the way out and then back in.

To be honest im getting really frustrated with it.

Can anyone give me some insight?

 

[Wile E. coyote]

I have to same lens, nikon fit though and haven't had any problems with it. Used it both my D50 and recently on my D80 and found it quick to focus, even in low light. Don't know why you are having problems :shrug:, sorry I can't help more than this.

 

[mikeyb]

Thats fairly normal for this lens, the Nikon fit version has an HSM motor, the Canon version does not. Lack of light will cause it to hunt and miss the focus, funnily enough my Canon 50mm F1.4 does the same as your Sigma.

Mike.