If you typically photograph fast-moving, active subjects, you need autofocus. (If f/1.4 is your reason for considering this lens, be forewarned that it's difficult to nail even slow-moving subjects consistently sharp at that aperture.) Likewise, if you’re not willing to obsess a bit over manual focusing, stick to AF lenses. At f/1.4, depth of field at near and middle distances is shallow enough that meticulous attention to focus—if not a viewfinder magnifier—is required. If you don’t have the patience, there's no point in paying for f/1.4, because you’re not going to get adequately sharp subjects at that aperture. Get a slower lens, such as the Zeiss 35mm f/2 ($1,117, street).