Hm, decided to send my lens to be calibrated by Sigma. Came back, still front focussing - -"!!
Want to bring it back again but the lady told me the technician is on leave. Only available next week, sigh. I guess I have to use AF Fine Tune on my camera first until next week.
The sad part is, I specifically told the lady to make sure it's calibrated perfectly as I am planning to use it on this coming weekend. And she told me, no worries, that's what the calibration for, we'll make sure everything comes good![]()
It can only be calibrated at one distance and it's body dependent. That's why they asked for the body you intend to use with the lens and use that for calibration as well. I think the calibration distance is 20x the focal length, so for 50mm lens, they calibrate at 100cm distance, so outside this range, there may still be front/back focus. For example, my 24/1.8 is good for mid distances but it's front focused for infinity and back focused for closer shots.. :sweat:
I think that's going to be my last Sigma lens. Even AF Fine Tune on D300 could not fully address the problem because the front/back focus is not consistent throughout the focusing range. Meanwhile, I'll wait for Nikon's reintroduction of their renowned AiS fast prime lenses in AF-S flavour. ;p