I've often wondered about how PJs from the 50s and 60s who shot Rolleiflexes were able to manage that - the film transport mechanism in the Rolleiflex is just brilliant with perfectly spaced frames every time, but that damned door and the knobs to lock/unlock the loaded film and take-up spools are a royal pain and there's no way to do it quickly that I have figured out yet. The Leica mechanism in the LTM cameras looks like it could frustrate the casual, but is more sensible than the Rollei! At least Leica went to a permanently installed take-up spork (well, that's kinda what it looks like anyway - a three-fingered spork) in the M series.