It's bit sharper @300mm F2.8 than Canon 300mm F4 L @F4. But at 300mm you would get similar reach about 280mm of Canon teles.

Excellent lens! I'm extremely happy with this product, especially when paired with the Sigma USB Dock.

This 3390g behemoth of a lens fits snugly into Sigma's Sport line of glass and is designed to be mounted to a tripod rather than hand-held. This leads it to be rather more specialist than many lenses in test, though doesn't detract from its image quality.