Ok, I would like to bring up this topic again (sorry!). I have a Canon 350D and a new Sigma 70-200mm F2.8 EX DG with a back-focusing problem.
Canon probably won't touch the Sigma and Sigma tells me to check the camera out first. My point is this: Is the problem with the lens or camera or both? Why is it they say that the lens must be calibrated togehter with the body? Shouldn't they follow the same autofocus protocol and the same reference specs/signals?
What if you have more than 2 bodies and 2 lenses? How do they calibrate all of them? If you sell off the lens, would the next buyer have to calibrate the lens again to his body?
When I brought my lens to Sigma, they asked me to bring along the body for testing. According to the tech (Harry), he said my lens contained a new re-writeable chip (after checking the serial number). After doing some testing, he managed to recalibrate the lens for me after about 1 hr using their new equipment.
I was fortunate in that I bought the lens with the original sigma warranty i.e. non-grey set. This meant I got the recalibration for free.
Do other 3rd party lenses (e.g. Tamron and Tokina) suffer from these front/back focus issues? How about other bodies e.g. Nikon, KM, Pentax etc?
Any comments?
Canon probably won't touch the Sigma and Sigma tells me to check the camera out first. My point is this: Is the problem with the lens or camera or both? Why is it they say that the lens must be calibrated togehter with the body? Shouldn't they follow the same autofocus protocol and the same reference specs/signals?
What if you have more than 2 bodies and 2 lenses? How do they calibrate all of them? If you sell off the lens, would the next buyer have to calibrate the lens again to his body?
When I brought my lens to Sigma, they asked me to bring along the body for testing. According to the tech (Harry), he said my lens contained a new re-writeable chip (after checking the serial number). After doing some testing, he managed to recalibrate the lens for me after about 1 hr using their new equipment.
I was fortunate in that I bought the lens with the original sigma warranty i.e. non-grey set. This meant I got the recalibration for free.
Do other 3rd party lenses (e.g. Tamron and Tokina) suffer from these front/back focus issues? How about other bodies e.g. Nikon, KM, Pentax etc?
Any comments?