I sold a brand new 600 EX-RT to a member here and I get this pm today
I read the manual from start to finish,
put it on my camera ( Mark IV) and all it does is
want to stay in TTL mode.
When I go back to custom functions I can set it back to
ETTL, As soon as I press the shutter it jumps back to TTL."
I took the flash on a trade from a well established(232+) member and it was indeed new and I never used it. Could this be an issue with the flash or could the user not possibly doing something right? I don't know so i thought I would ask here from people who do.
update: he messaged me and says it is working so maybe he was just doing something wrong, I dont know
That was a known problem with the 580EX II shoe design. Contact issues between the flash foot and camera hot shoe made the flash switch from ETTL to TTL. Canon came up with a retrofit and the 600 has this new design installed. I own two.
I have read of this happening once to another 600. I believe cleaning the contacts solved the problem. The cameras hot shoe might need a touch up. Also that foot contact pressure can be adjusted but I can't see that being required on a new flash. You may want to let the purchaser know this. I may or not help but it is a starting point.
