bought this lens primarily for its incredible sharpness and optical qualities. The very fast maximum aperture (f/1.4) was only a secondary consideration. I took the lens to a photo session yesterday and was not disappointed. I took almost 200 pictures with it. The sharpness, clarity and color saturation of the images I took with it are on par with my best "L" series lens, which costs a lot more than this one! Please note, however, that sharp, clear images require an aperture of f/4.0 or smaller (higher f-numbers, up to f/22). Opening the aperture wider than f/4.0 softens the images. At f/1.4 the images are very soft, much softer than I'm willing to accept. In order to preserve image sharpness and overall quality, I think the best way is to increase the ISO when needed and avoid using an aperture wider than f/4.0 (or use a flash). Also note that this lens does not have IS (Image Stabilization), which means that the shutter speed should not be faster than around 1/50 second. If the shutter speed is less than 1/40th of a second, blurry images are to be expected. Finally, note that this lens only works as a 50mm "normal" focal length lens on full-frame cameras. If your camera has a 1.6 crop sensor like mine, this lens is equivalent to a short focal length 80mm telephoto lens. In summary, if you're looking for a lens that takes incredibly sharp, clear, and crisp images at apertures of f/4.0 and higher (up to f/22), you'll be very happy with this lens. However, if you're looking for a lens that will produce very sharp, high-quality images at wider apertures in low-light situations, you're better off with the 50mm f/1.2L lens, which handles low-light conditions much better. But this lens costs about 4 times as much as this lens!