A1ex: thank you and dfort's patience with my somewhat ignorant questions. I very much appreciate your efforts to solidify the use of Live View and audio triggers, and didn't fully realize the recent posts on this thread were working on just that.
I am not sure you understand my context in mentioning “Cycle Time” and the use of a flash shoe without also triggering the shutter. My work with these Canon cameras and ML are to produce a poor man's movie film transfer and digital restoration system. ML allows budget minded, professional quality transfer, and Blender's compositor feature allows an amazing set of post production tools, before the result is sent for final rendering in AVI Demux.
A ten minute sound film requires 14,400 individual frames to be captured in the camera. This number of cycles would destroy the shutter of my 650D, and to my horror, the mirror-less EOS M still employs mechanical components which would quickly wear out under this kind of use. My only option, with these cameras, is ML and the Silent Pictures feature.
Although I am recording raw video, the system is synchronized to only take one exposure for each frame of film.
With so many frames, it takes days of frame by frame image capture to digitize an average movie. My definition of the term “Cycle Time” refers to the interval required for the camera to capture an image, save it, and then recover and be ready for the next frame. The MLV_Rec feature is great and allows frame capture at a rate superior to saving individual DNG images. My film capture system would still benefit greatly from any improvement in the time it takes to save images.
The flash shoe question was related to my quest to find a way for the camera to indicate to my external equipment that it is ready for the next exposure. As a SD memory fills, it takes longer and longer to save each successive frame. Right now, my system has to “guess” when the camera is ready, before it initiates an exposure. This worst case guess is what defines my cycle time, for each frame. If I could generate a machine readable “yes, I'm ready” signal, that would be my trigger to initiate another exposure (rather than using a worst case dumb timer). I had hoped I might use the flash shoe switch closure to signal this. If that use isn't possible, my only other option would be to flicker the camera's status LED in a machine readable pattern, and have a photocell or photodiode sense the event and signal my equipment.
Between you and dfort, I appreciate you addressing most of my earlier questions. I will wait now for you guys to have something to test.
The only remaining issue from my earlier post, is the problem of preventing my EOS M from dropping into Power Save standby, when recording in Silent Pictures/Simple resolution. This mode would be very useful and fast for 8mm capture. Simple resolution may be about all standard 8mm needs, given it's very small frame area. It seems that the camera drops into power save standby, as defined by the LCD timeout value. Could this be over-ridden when using the camera in forced Live View? Keep your priorities, but please also consider this one in due time.