For all we know there is a 1-2 interval in analogue as well, who is to say that film starts being exposed the instant light falls on it.

You could of course test this by rigging up two cameras to take the same shot at the same time of say a scrolling wave form on an oscilloscope (or some sort of hires digital timer on a screen/display, a second hand on a clock isn't going to work due to parallax issues). But I'll bet any difference (either way) is so small that it will be lost in the noise in the data.