Backup Camera

So my gear is listed below, I need/want a camera that will basically only get used if my 5Dii quits working. I've gotten a couple requests now to shoot friends' weddings/engagements and other events where I'd be worried to lose the ability to take pics....

I used to have a 7D but I liked the 5D better so I sold it. It would be nice to have the same battery but it's not a necessity. I think a crop is fine in this case, cheap is better. I used to have two 5Dc's but I sold them. Maybe I should have kept one?

Should I wait for a 5DIII and use the 5DII as the backup??? Not exactly cheap but I'm also a gearhead. Remember, I would never use the camera unless my primary failed....

Any ideas?

I've been in this a little longer than the average member--My initial SLR had the first in camera metering system.

20 or 30D's have a competent AF system --a decent sensor-- and are dirt cheap-- FF is highly overrated for prints smaller than 16 x 20 IMHO.

I keep one of both for remotes that go in harms way--and both are good backups that have been retired from primary duty

I also use a 5D II, but we use my daughter's 60D for backup and for second shooter. Performs well, shares batteries, but of course different memory cards.

There are two possible approaches...

If using both cameras regularly, expecially if switching back and forth quickly during a fast moving event, it's nice to have two of the exact same model. It makes the swaps more seamless. Having two cameras also might extend each of their lives... If you swap back and forth and spread the work around. And, of course, all the accessories for one will fit the other perfectly.

The other approach is to get a camera that's different in ways that complement your primary camera, such as mixing a crop sensor with a full frame to "leverage" your lens kit.

A 60D or even 50D might serve well, in the second role. However, while a 60D uses the same battery as your 5DII, it uses different memory cards (as noted by jrscls). OTOH, a 50D uses the same type of memory, but different batteries. No easy answers, I'm afraid!

easiest answer points to getting a 7d again, same battery, same cards...

7D is the best option, but if you're money conscience, consider a used T2i. It's similar resolution as your 7D and has similar AF and FPS as your 5DII. If you don't like the size, idea, Rebel stigma, etc., pick up a used 50D for about the same cost. I picked up a T2i for my son to use. I wound up using it as much as my 5DII for the crop factor.

60D also uses the same battery, and it cheaper than the 7D, but it does use different cards (though SD cards are very cheap).

7D/1d3 for teh best combo.