5D mkii 580exii not recognized by 5Dmkii

[Skirball]

Is the 580 on?  Does a test flash work?  Is it in the hotshoe, or are you using a cord, or a wireless trigger?  Is it fully seated and locked into the hotshoe?  Do the contacts on both the flash and the camera look ok (any corrosion, damage, etc)?

It's hard to guess without giving us any information.  But there isn't any reason why a 580exII wouldn't work on a 5d2.  I would start with a basic sanity check of the above, if everything looks ok I'd clean the contacts with IPA and put in a fresh set of batteries just to be sure.  If it still didn't work I'd try to borrow another flash (or go to a camera store) and isolate if it's the camera or the flash.

[lennagi]

. I am past all your suggestions. I believe my problem is mechanical. I can slide the speed lite into the hotshoe And without locking it, itworks if I tilt the speed lit backwards and stops working if I tilt it forward and works again on tilt back. When I Lock the speed lite in place, it does not work because the locking mechanism tilts the speed light forward. I can get it to work if I put pressure with my hand to tilt back, but when I release the pressure it tilts forward and doesn't work. I removed, cleaned and replaced the rubber grommet on the lock, cleaned the contacts, checked that the pins have free movement. Probably will send it to Canon unless someone has an easy fix.

[TCampbell]

Ahh.... sounds like you have the "loose shoe" issue.

Contact Canon support.  The shoe on the bottom can become loose and this causes it to lose the solid electrical connection needed to function.  It's a known issue with the 580EX II and I think they've even revised a replacement shoe which is less likely to have such a problem.

You can find YouTube videos and other articles if you search for "580EX II loose shoe" -- but unless you _really_ know your way around thesee sorts of repairs, I'd suggest having it serviced professionally to avoid anything going wrong. 

[lennagi]

Thank you. I will contact Canon

[TCampbell]

I said "loose shoe" but should have written "loose foot".  The "shoe" is on the camera. The "foot" is on the flash.  It's the foot on the flash that will sometimes become loose.