Yes, at 1.8 it does not produce the same quality as canon 50 / 1.4 or any sigma. Because the lenses are of different price ranges, but in its class, for its price, it is really handsome and deserves to be in the bags of all canon owners Examples:
Canon EOS SLR Camera Lens EF 24-105mm f/4 L IS USM
124 Review
Nikon 50mm f/1.8D Lens: Perfect for Nikon DSLR Cameras!
97 Review
New Nikon 18-105mm Vibration Reduction π· Zoom Lens with Auto Focus for Nikon DSLRs
104 Review
Canon EF 40mm f/2.8 STM Lens - Fixed Black (6310B002) for US Cameras
76 Review