Originally posted by kypfer This is all fascinating stuff ... a totally un-plumbed depth for me
So, I've been reading and playing and I've come up with a query ... given similar exposures, is there any difference between "Multi-Exposure - Composite Mode - Average" and "Interval Shooting - Composite Mode - Average" or can one be considered an extension or sub-set of the other?
They are identical except for who triggers the shutter for each shot.
Multi-Exposure: the photographer triggers the shutter when they want (including using any external triggering accessories). Thus, the photographer can reframe each shot of the composite, change exposure for each shot, and optimize when they fire each shot.
Interval Shooting: the camera triggers the shutter at exactly equally-spaced intervals with the first shot starting under photographer control or via a timer/alarm. In general, it's used with a fixed camera on a tripod although a clever photographer make composition or setting changes in the delay period (e.g., with a 5 second interval, they have maybe 4 seconds to change the setup between each shots.) If you want the strobe-effect of subimages with movements exactly proportional to their velocity, interval shooting provides accurate timing.
Given that the photographer could act like an interval timer in Multi-Exposure mode but the camera in Interval Mode could not act like an intelligent, scene-sensitive photographer, I'd say Interval Shooting is a subset of Multi-Exposure.