Canon EF 24mm f/1.4L II USM EF24mm F1.4L II USM Instruction Manual - Page 8

6. Hood 7. Filters (Sold separately) You can attach filters to the filter mounting thread on the front of the lens. ¡Only one filter may be attached. ¡If you need a polarizing filter, use the Canon Circular Polarizing Filter (77mm). The EW-83K hood can keep unwanted light out of the lens, and also protects the lens from rain, snow, and dust. To attach the hood, align the hood's attachment position mark with the red dot on the front of the lens, then turn the hood as shown by the arrow until the lens' red dot is aligned with the hood's stop position mark. The hood can be reverse-mounted on the lens for storage. ¡Part of the picture may be blocked if the hood is not attached properly. ¡When attaching or detaching the hood, grasp the base of the hood to turn it. To prevent deformation, do not grasp the rim of the hood to turn it. ENG-7