Canon 312 XL-S - Manual (Page 32)

Focusing
The Canon 312XL-S can focus as close as 1.2
meters, but distance must be estimated. After
determining the distance between camera and sub­
ject, turn the focusing ring until the proper distance
is aligned with the index in order to focus correctly.
The focusing ring may be set at or in between the
numbers. The row of white numbers represents the
distance in meters and the row of green numbers
represents the distance in feet.
Film Plane Indicator
When precision focusing is required, measure the
exact distance between subject and film plane
indicator and adjust the distance scale accordingly.
Using the Zone Focusing
When filming outdoors under a clear sky, the depth
of the field is increased and you can simply use the
3 or 10 red zone markings without focusing exactly.
For close shooting of up to about 7 meters, set the
distance ring at 3; for shooting subjects farther away
set the distance ring at 10.