presspass
filmshooter
I have both Leica IIIa cameras and a Canon IVSB2. The Leicas are smaller and, with a 35mm Elmar or collapsible Summar 50, very pocketable. The Canon has a brighter viewfinder, a much more user-friendly rangefinder, and both share the same viewfinder window. If size is the controlling factor, a IIIa Leica is hard to beat. If you want a better rangefinder and a viewfinder that can be adjusted for 50, 100, and 135 lenses, the Canon is the obvious choice.