I got a cheap 760nm IR pass filter from ebay recently just to have a muck around. I knew the 5DmkII was VERY insensitive to IR but I was surprised at just how insensitive!
I have also checked it on the mkIII with the same lens and it is MUCH more sensitive.
These were 2 minute exposures at ISO1600 with my 40mm f2.8 wide open.
Taken of and around the Tacking Point lighthouse in Port Macquarie while I was back there visiting my parents over the holidays.
Less compressed versions and a couple more on my blog here:
https://hughsblog.wordpress.com/2014...oint-at-760nm/