Canon EOS-1D X Mark III DSLR Camera (Body Only) - Manual (Page 341)

: Spot AF
The camera focuses in a narrower area than 1-point AF.
Effective for pinpoint focusing or focusing on overlapping subjects such as an animal in a
cage.
Note that the small Spot AF area may make focusing difficult in handheld shooting or for
moving subjects.
: 1-point AF
The camera focuses using a single AF point < >.
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