Ok, so here's the problem I'm having with this supposedly amazing lens: When zoomed all the way out to 24mm, and I try to focus on the subject, then reframe to take the picture, my focus falls to the background rather than staying on the subject which I originally focused on. This happens on almost all images taken at 24mm with this lens. Is this a lens defect or am I doing something wrong? Here is the camera and settings that I'm using: Canon 40D One Shot - Focus Mode Shutter speed - plenty fast enough to stop motion (often around 1/200) Auto focus point set to center point; I aim the center point at the subject, halfway depress the shutter to set focus, then recompose to set the subject off center and fully depress the shutter (I've used this method with the 18-55mm IS and 50mm 1.8 and have had no similar issues) Please help because I'm ready to send the lens back! WAY too expensive of a lens to be having these kind of problems. Thanks.