Originally posted by adelante I have a 96 vintage Sigma 70-210 F4-5.6 lens that I've been happily using on my 1stDL for a few years. The AF has stopped working, there is tension from the motor when the camer is in AF mode but the indicator shows MF in the viewfinder. Ive tried the lens on my K20D with the same result. Ive also tried cleaning the contacts with a pencil rubber but no avail.
Have I missed anything that I should be checking and are these lenses worth repairing ?
Hrm, for thoroughness' sake, do you have other AF lenses that still work?
I suggest that before you try anything else, ...be sure of fresh batteries, and maybe even clean those contacts again. I'm not sure what would make the VF display claim MF... but it sounds as though the lens mechanism is jammed. (You might try jiggling or turning the screw drive connection on the lens, in case it's just stuck by some odd circumstance.)
I've never had an AF lens apart, so I don't really know how easy they might be to service: but odds are it may be cheaper to replace than pay to repair a lens like that, unless it's something very simple and you really like that lens. Generally, it'll be as costly to repair a cheaper lens as a fancier one, and lenses like that are pretty common.