Canon AF514XL-S - Manual (Page 67)

Instant Focus Lock Button
0
The effect upon focusing of pressing the
instant focus lock button depends on
where the focus mode switch 0 is set.
“N" Setting of Focus Mode Switch
The moment you press the instant focus
lock button, the iens is locked at the point
it was focused just before you pressed
the button and it stays iocked until you let
go of the button. Use this feature when
you suddenly wish to lock the focus dur­
ing the course of normal autofocus film­
ing.
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