« on: April 09, 2012, 12:16:28 PM »
In terms of 'overall' AF performance, I'd stack rank the recent bodies as follows: 1D X > 5DIII > 1DIV > 1DsIII > 7D > 60/50/40D > 5DII > xxxD.
I'm surprized that the 60/50/40D > 5DII. I always thought the 20D through 60D had identical AF systems.
I'd approximately rank them as 300/2.8 IS II = 400/2.8 IS II > 300/2.8 IS = 400/2.8 IS > 500/4 > 400/4 DO > 300/4 IS = 300/4 non-IS.
But wouldn't 400mm f/2.8 IS II >> 300mm f/2.8 IS II+1.4x TC? That's more of an apples-to-apples comparison and similar to framing the OP is talking about.