Hi,
I bought a Sigma 17-70mm lens last year. It was fine to begin with, but whenever I have my Canon T2i in auto focus mode it focuses incorrectly, causing the image to be totally out of focus. As a result, I constantly have to keep the Canon in manual focus mode which isn't ideal as this was meant to be my quick multi-purpose lens. I do not have this issue with any of my prime lenses, or the kit lens that came with my original Rebel XSI. Is there a fix for this issue?
Comments
Are you sure you haven't accidentally switched the lens to MF instead of AF?
Basically it goes back and forth trying to find something to focus on, and then finally stops with the green square and the happy "beep beep" to say the image is in focus. The result is a totally out of focus image. If I want to use the lens now, I have to put it in MF and focus myself.
Sorry, I can't help on this one.
I've done some trawling around the internet and it seems you are not alone in experiencing problems with autofocus on this lens. It seems that in most cases, the problem is resolved when the lens has been returned to Sigma. I don't know what costs would be involved if you are out of warranty.
Regards, PBked