Review on Sigma 50-500mm f/4.5-6.3 APO DG OS HSM SLD Lens for Canon DSLR Camera - Ultimate Ultra Telephoto Zoom Lens by Adam Vang

This lens has a very high rating on Dyxum. I agree. Surprisingly sharp wide open. I tested the lens chart at 500, 400, 300 and 100mm. Surprisingly spicy! Note: Yes, it's hard. If it were possible to get all that big glass in a lighter package, that's what you'd expect from Sigma. I find the lens well built - sort of a tank. Sigma supplies a two-piece lens hood. Use 1 part with full frame camera, use both parts for APS-C. They also come with a reducer ring to allow the use of 86mm filters when connected to an APS-C camera. 95mm full frame filters must be used for full frame use. Helps reduce costs slightly for APS-C users. My only wish is that Sigma have a "tuning base" for this lens. My lens shows very negligible front focus on test charts - not enough to send this monster to Sigma for readjustment.