Sensor-triggered photography

Piranha215 wrote:

Thank you for that information; it is most useful. One of the beauties of my system is that the sensor responses can be cascaded sequentially, in any number.

Not to be cute, but that's worked with CHDK for nearly a decade. I have fleets of PowerShots that I use that way, from $70 20MP ELPH180 to $130 16MP 50x Zoom SX530HS, with various internal/external triggering. Of course, I'm a computer engineering professor, so perhaps it's not shocking that I and my group are pretty good at this stuff.

Anyway, there is still value in having a good external controller, and an Arduino nano makes a nice sub-$2 plaform.

The key issue I'd be concerned with is release timing. Most digital cameras have significant delays from shutter trigger to shutter fire -- often between 1/100s and 1/10s. Using USB-power-sense triggering with CHDK, you can easily sync to within 1/1000s (which is the internal OS scheduling jiffy in the cameras), and with some work can usually hit within 1/30000s for trigger of the mechanical leaf shutter (which, incidentally, can do shutter speeds up to 1/10000s or faster on some cameras under CHDK). BTW, the CHDK motion detect code module examines the rear LCD live feed, so it has a max of around 1/24s latency to grab a frame from the live feed, but triggers almost instantaneously when it has the frame. Overall, this makes CHDK PowerShots excellent cameras for use with external triggers too; in fact, you could also have the camera OUTPUT a trigger to an external device using USB, camera LEDs, etc.

What detect-to-trigger latencies do you measure on the cameras you're using?  Which cameras?