As Neuro noted, there is only one type of better beamer, but different part numbers fit different flashes. The flash may scare shy birds, but you get the image first.
It doesn't matter 7D or 5D, lighting will help.
This is a image taken with a 1D MK III, 100-400mm L at 400mm with a better beamer. I had a comparison image without the flash, but its lost. There were some nasty shadows that made the image awful without the light.