Autofocus on Sigma 24mm 1.8

Demian

Alright, I absolutely love this lens, but it has one huge problem: The autofocus is totally inaccurate. I've tried doing the microadjustment, and it works, but -only- for the distance I calibrate it at. So if I calibrate it at 1 foot, it works great at that distance but the AF screws up at 6 inches or two feet!

Obviously, I can crank up the aperture, but that kills the whole point (I love having relatively narrow DOF at 24mm)

Sooo... I guess my questions are: Is this a known problem with the lens? Can it be sent in for repair? Or is it just something I have to live with?

ziggy53

Many lenses have difficulty with perfect autofocus, near versus far. My Canon EF 135mm, f2L USM will not accurately autofocus at close focus distances, for instance, even though focus accuracy is excellent at my normal shooting distances.

Yes, it's possible for a lens manufacturer to tweak a lens to improve autofocus throughout the range of focus. Often it can require several trips, however, in order to get it right. Sometimes, the lens never works as well again for anything.

Many times you can shift into manual focus mode on the lens, and use manual focus with focus confirmation from the camera to produce desirable results. I suggest trying that approach for the lesser used focus distances, and calibrate the autofocus micro-adjust for the majority of your use of the lens.

Demian

Thanks for the advice.

I think I will end up contacting repair then. I mainly need the autofocus at close range (where it's too volatile to make much use of the MA) :X Hopefully it comes back in one piece!

Manfr3d

Sounds like it needs service. My copy (sold in the meantime) focused slow but accurately at all distances on a 5D2.