http://cgi.ebay.co.uk/Sigma-AF-Tele...0096401487QQcategoryZ4687QQrdZ1QQcmdZViewItem I'm after a lens that's long and good quality, but I can't seem to find any information on this lens. So I just want my long, and fairly sharp, lens but I don't know if this would fit my 20D or if it's the older Canon mount. Also, I'd like to ask if any of you have any information on the quality of the lens. I would really appreciate your help. I know that it will be heavy, but for that money, I'd take that pitfall easily. I really want to get into wildlife photography and this would be a "set up and stay there" lens which I'm okay with. So weight isn't the issue, it's more the build quality and mount compatibility. In an ideal world, it would also be compatible with a full frame EOS camera for when I eventually upgrade. This would be my second lens, leaving a huge gap between the 50mm F1.8 Mk II, which would possibly be filled by either the Canon EF 24-105mm or a third party equivelant. What do you guys think of the lens for sale at the above link? Is it worth going for it? P.S. Another small point, I'm okay the idea of a prime telephoto, if the quality is superior to a telephoto zoom. P.P.S I'm okay with shooting at fairly high ISOs to get the right shutter speed, about 1/600s. I shoot RAW and can use noise ninja when I get it.