Originally Posted by numee
It's "dayum" if you do and "dayum" if you don't....own a 20D and 30D and had the same problem....using non-canon lenses....
Finally got a Canon Rep. to give me the "skinny"...both the 20D & 30D have contacts set for Canon lenses...
Not to say non-canon lenses won't work...but you have to send them back to the Mfg. example; Sigma, Tamron, Tokina....and they will modify the lenses. If they are under warrenty, will only cost you shipping..however, if they are not warrenty...the Mfg. will "dob" you with a charge...
Oh, by-the-way, have Sigma lenses on both cameras..
I don't think the Canon Rep gave you the "skinny", he gave you the "baloney".
The contacts are virtually identical in all of the lens that work for the Canon line of cameras. There is, however, a chip (a computer chip) inside the lens that controls certain electronic and interface issues. If you buy an older Sigma or Tamron lens, for example, then there might need to be an update made to the chip. But the contacts would not be changed at all. However I've used Sigma and Tamron lens on my Canon 10D and 20D that go back almost 7 years and they have all worked perfectly. I still have a Tamron 28-300 that I used to use on my old Elan Film camera and it worked perfectly there also. I later sold the Elan on eBay along with the Tamron 28-75 f2.8.
In the case of the original post, it can't be a chip issue or the lens would not have been working for the last year. What sometimes happens, on any lens, is that some of the electronics that are inside the lens (that you don't see) can come loose and as a result, you have to have a repair.