With a 11-24 f/4 on pre-order, I was thinking about getting some gelatin film(s) for the rear holder. If I remember, the holder on the existing lenses (14L, 8-15L, 17-40L, etc.) are all the same size. Can anyone confirm? If so, then it's probably pretty safe to assume Canon will stick with the same size. Also, does anyone know the approximate dimensions of the gelatin that fits? I thought Canon had a template in the manual or on a sheet of paper, but I can't seem to find that online - maybe it was from another manufacturer.