How does eTTL work? Does it take exposure or work on distance and aperture? If I put an ND filter on will it adjust the length of flash.
It is a long time since I've used a flash, back in the days of Guide Numbers and I used a suck it and see method for bounce.
I haven't got a flash yet but if I set up a flash on a tripod say in a triangle 60 degrees from the line of view of the lens and a white card the other side of the object in line with the flash; (artificial scenario) how do I work out exposure?
Maybe I made that a bit complicated but stopped at adding a ND filter and strong backlight; all I want to know is how it works.