Hello,

I shoot weddings and am about to purchase a 5D and some flashes. I
always shoot with a bracket to switch between a vertical and
horizontal, without weird shadows.

Do I gain anything from buying canon 580's instead of 550's? It is my
understanding that the distance info is cut out of the algorithem when
the flash is off camera, and or bounced. (makes sense).

There is some money to be saved. (three flashes)

Thanks!

Tor