« on: November 07, 2012, 07:49:51 PM »
5D III has some issues with AF-Assist Beam under low light - Speedlite 600. You might want to double check.
Based upon this I change my earlier vote for the Canon 600EX and vote for the Yongnuo YN565-EX instead. It can provide focus assist in total darkness (went into a bedroom closed all doors and curtains at night and could take pics of anything in any corner of the room with almost instant AF on my 7D + 24-70).
The AF assist beam is absolutely crazy; will effectively light up a dark room. Just took this with my iPhone of the weird beam it throws out Kinda looks like Lips with heavy Pink Lipstick
That's the same AF assist beam thats on the Yongnuo YN568EX as well, and my 5DIII focuses very fast in the dark with that. Canon 580EX II comparatively puts out AF assist beam that is much less obvious.