The 580EXII users manual indicates as follows (ETTL mode):
...Turn dial to set flash coverage.
...If <M> is not displayed, the coverage will be set automatically
M is not display but only dashed lines indicated (_ _ mm). Is this correct or should there be a value for 24mm indicated or am i doing something wrong?
Also states that when connected to a compatible camera little rectangle box appears which I do not have.
Posted in light forum as well.