i won't say "some"
talking with a huge camera service they told me lots of cameras , lots
mine seems to focus correctly ,by the way i used the 1d mark IV , 10/10 shots perfect
Out of how many sold? That's the problem with saying lots or many in that it is extremely subjective. The percentage of defects could be substantially lower than the other models or Nikon given we don't have exact numbers. All we can say is indeed there have been some repairs required. Beyond that it is purely speculation.
I use spot af when doing portraits or shooting something stationary in a clutter environment like a sitting bird in a tree. I use single point with expansion when shooting moving subjects with an unclutered background like the sky. I don't use full auto unless just playing around and testing. I don't find myself use zone af much either. Most everything else is just using a single af point. My 7d is vastly more accurate than my 5d2, xti and T2i. I also prefer the 7d metering compared to the 5d2.
