The EF 15 mm lens does not use standard front mounted filters due to its wide field of view. Instead is has a pocket at the rear of the lens into which 31mm square acetate filters can be placed
The Variable Aperture AE control will not operate, but you can manually adjust the aperture ring of the lens. A basic exposure guide to follow for bright sunlight (with distinct shadows) is to make a fraction representing the shutter speed needed at f / 16 by putting a "one" over the film's ASA rating. With a film of ASA 100, use 1/100 sec.
