So, I get that that Mk3 AF is very advanced vs. the Mk2, etc... what I am finding, however, is that during low light wedding receptions (dancing) the AF takes a second or so longer to lock on that the Mk2 or Mk1 did. I've changed the settings to release priority vs. focus priority so I can at least get the shot even if focus is not locked, but I am somewhat stunned that this advanced AF takes so long to lock in these reception situations. First, I am wondering if there is a setting I am missing, and also is anyone else seeing this? My second shooter and I are both having the "problem", so I thought I would ask. Thanks all!