There are lockers that you pay for (I think it was $8 per day?) at the entrance to the parks. One day last week, we brought our camera and a pack to Universal. We tried to use the free lockers at Men In Black. I know its a very crowded week but the line to get a locker was longer than the line to get onto the ride. The video screen in each section stated that all the lockers were in use. People would come up, empty their locker, shut the door and then see the glowing light that indicated the locker was available. I guess they thought that meant the locker wasn't cleared of their info yet, so over and over we saw people press the button. That kept the lockers unavailable for others to use. The video screens messages changed to something about no doors being available. My suggestion would be to forgo any bags whenever possible and if you have a large camera, plan one camera day.