Wider than the Canon 24 F1.4L, there are no lenses in the lineup faster than F2.8. Do others think there would be a market for a 16mm F2L or 18mm F2L prime lens? It would be a stop faster than a 16-35/2.8 which would be awesome for indoors shooting, night sky photography, photojournalism, etc. Would a lens as wide as 16 or 18mm at F2 be able to retain a 72mm or 77mm filter size?