I own a Sigma 400MM 5.6 HSM with Macro, manufactured in 2001. It will not work on a Digital Rebel (Error 99) and Sigma has told me it cannot be upgraded. Does anyone know if there is a third party that can do an upgrade? It's a great lens on my Film EOS.
Error 99 is a general fault not necessarily related to the lens (it also happens on Canon lenses)!
The re-chipping only applies to non
-HSM lenses, and only to lenses manufactured before
2000... Plenty of EOS 300D and 10D users of the same lens over here: http://www.pbase.com/cameras/sigma/400_56_apo
Try to clean the contacts or bring it to a store and try on a different body :idea: