thank you all for taking the time to answer my question, the fact is
that I really don't like the 100-400 (there's one page regarding my
dissapointment with this lens) and I was thinking about photographing
let's say big birds like eagles.the closest I could get to one was 50m
or so, will the flash still give me some light at that distance or is
useless? (the 580exll)
what about macro using this flash? with the 100mm f2,8 lens (not the
IS version)
thank you