Originally posted by Clem Nichols I've just noticed a back focus problem on my Sigma 30mm f/1.4 EX DC lens. Am I right in thinking that this is something the techs at the Sigma repair facility in New York can correct? Thanks.
DN
Hum, I wonder. I´m not an expert on this topic. However....
If the autofocus system of your camera is working with pixel contrast ratios and a focus stepping motor plus feedback system. Wouldn't that mean that the camera decides when a something is in focus? Measuring through the lens, independent of the internal mechanisms of the lens. Maximum pixel contrast = in focus?
If this is how it works, and if you are suffering of BF problems, how could the that problem than lie with your lens?
Isn't it allways the camera that is at fault here?
- Bert