Hi all, new to the forums but a long-time lurker! I have an old film-era Sigma 500mm f/4.5 AF APO with EF mount, and I'd like to know which digital Canons (if any) will work with it. There seems to be some conflicting information in this regards, but the general consensus seems to be that all DIGIC II and later models are incompatible with old Sigmas. More specifically, any aperture other than maximum (e.g. f/4.5 on the 500mm) will result in an err99 error. All fine so far, however there are conflicting accounts about compatibility with earlier Canons, which I've surmised below. All pre-DIGIC II DSLR's are compatible with old Sigma lenses (i.e. 300D, 10D, 1DS (Mark 1), 1D (Mark 1), D60, D30) All pre-10D models (i.e. 1DS (Mark 1), 1D (Mark 1), D60, D30) Only non-DIGIC models (i.e. 30D and 60D) No digital at all. If anyone has first-hand experience with using old Sigma lenses with these models, please post your findings below. I'm especially interested in hearing from 1D and 1DS owners. Thanks!