I recently acquired a Sigma 70-300mm APO zoom lens with EF canon fit from a friend. I naively assumed or at least hoped that it would work with my Canon 450 D. It doesn't and Sigma's advice was that if it was 'rechipped' it would work but service is now closed as parts have been discontinued. This is very frustrating on a no of counts. If you purchase any Canon EF lens you know it is going to work with any Canon EOS camera. Having researched this further it seems Sigma will often have to 'rechip' your lens if you upgrade your camera, something to do with Sigma having to reverse engineer Canon's protocols and in my case the 'parts' are no longer available. I have also read that 'rechipping' is actually just updating the firmware. Does this actually need a new part? In this day of modern technology and the green environment I question Sigma's motive. Chips are cheap and I have a perfectly good lens that I know could work with my camera yet is likely to be consigned to the dustbin. Come on Sigma show me your Green credentials or are you more interested in churning out new lens.

Surely I am not the only person to be vexed by this issue, do join in. The more people that make their voice heard then maybe Sigma might take some notice.