In 5DMk3's manual (see pages 78-84), Canon divides the lenses in 9 groups based on how many Dual Cross-Type (if any), Cross-Type and Horizontal AF points a lens can exploit from the total of 61 AF points available.
The charts there are very nice, also the VIewfinder's blinking feature for the Horizontal AF points is ok, but how do I know in which group a lens belongs to, and I mean especially a lens which I do not own yet, a lens which I intend to purchase?
Of course, I mean lenses which aren't mentioned in the tables from the manual, either because are not from Canon either because are newer.
(For the nit-pickers: the aperture isn't sufficient to determine the group. For example there are f/2.8 lenses in groups A, B, C, D, E)