How many people actually know you could do this?
I know i might sound stupid but i actually didin't know you could "choose" the lenses that are supported..i thought it'a firmware thing..didn't know you could update it yourself…after so long, now then i realised…so thought i'd share this since if i did not know about this, i'm sure there are others who didn't know too..
The 5D3 can store data for up to 40 different lenses if you load it into your 5D3.
For at least some of your lenses, you'll have to fetch and load this data into your camera the hard way so that the 5K Mk 3 can correct it:
1.) Install EOS Utility software from the CD that came with your 5D3. My software disc is marked v25.0.
2.) Turn it off, and then put the lens for which you need data on your 5D Mk III.
3.) Connect the 5D Mk III via USB, then turn on the 5D3. (EOS Utility will start by itself if its not open.)
4.) Click the "camera settings" option from the main screen of EOS Utility.
5.) Under the Shooting Menu (red camera icon) in the EOS 5D Mark III window that opens, click the "Lens Aberration Correction" line.
6.) A new, bigger window opens with a list of lenses.
7.) Check the lenses you want. If you run out of your 40 maximum, uncheck some of the lenses Canon had checked as default.
8.) Click OK.
9.) Click Main Menu.
10.) Click Quit.