Quote Originally Posted by Chiller
Hello everyone. I am a newbie, and unfortunatly, my first post is a problem and not a photo.(that will be soon). I have been here for a few months now reading and viewing all the very inspirational posts.
My photographer friend and I both have the Canon Rebel Digital. I have a Canon, 70 - 300mm and he has a Sigma 70-300. The problem is, The canon lens will work on both cameras, but the sigma will only work on mine. On his camera, the sigma lens will not work in the program modes, and we get an Error 99 code, which in the manual is a battery problem. But it is fine in the regular modes.

I have contacted Canon, and they said that, they have never tested third party lenses and you basically take you own risk.
Does anybody know of a solution, other then swapping lenses for good. Also it the value of the two lenses basically the same, or would one be condisered better then the other.
Sorry for the long first post. I hope to have some photos to show soon.

Thank you all who reply in advance.

For whatever reason, Sigma lens often have to be "rechipped" or they act erratically. Sigma does this for free and the turnaround time is, from reports, pretty fast. Call then up and see what the procedure is for sending the lens to them.