Canon EOS 5D Mark III Instruction Manual page 97

23: One Shot
USM lens electronic MF
For the lenses below, which have an electronic focusing ring, you can
set whether to use the electronic focusing ring.
EF 50mm f/1.0L USM
EF 85mm f/1.2L USM
EF 85mm f/1.2L II USM
EF 200mm f/1.8L USM
OFF: Disable in AF mode
When the lens' focus mode switch is set to [AF], manual focusing is
disabled.
EF 300mm f/2.8L USM
EF 400mm f/2.8L USM
EF 400mm f/2.8L II USM
EF 500mm f/4.5L USM
: Enable after One-Shot AF
After AF operates, if you keep pressing
the shutter button, you can focus
manually.
: Disable after One-Shot AF
After AF operates, manual focusing is
disabled.
3 Customizing AF FunctionsN
EF 600mm f/4L USM
EF 1200mm f/5.6L USM
EF 28-80mm f/2.8-4L USM
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