Mornnb wrote in post #15829731
Yeah all very well on paper... but in practise the 6D has much more low light sensitivity than the AF system of a 650D. It is a more capable AF system, and the low light sensitivity is state of the art and the best any Canon camera offers. I think the lack of 11 cross types is a fair price to pay.
Also note the 6D actually has 19 AF points, but 8 are hidden, near the centre point. As a assist points. At least according to this. http://www.fredmiranda.com/forum/topic/1156576
Well, first of all let me tell you that I don't think the AF system on the 6D is bad. The 6D AF system better than the 650D AF system? In my opinion it just depends on what kind of shooter you are. If you always focus&recompose using the center AF point and shoot in low light (remember the center AF point on the 650D is dual crosstype while the center AF point on the 6D is only crosstype), then yeah the 6D is probably the best you can get (although I believe there is a Pentax DSLR which can also focus down to -3 EV). But if you're a rule-of-thirds shooter like me, then the 650D AF system is better. You'll have crosstype AF points located at the thirds of the image, while the 6D doesn't have any AF points located at the thirds of the image because of the small spread. Also, in low light the outer points on the 650D should work better than the outer points on the 6D since they are crosstype. I'm still not sure whether I'll buy a 6D or a 5D3, but if I decide to go for the 5D3, then the 1 crosstype AF point and small spread will be the dealbreakers for me. By the way, interesting find on the fredmiranda forums, however I'm still not sure if it's true.