Canon MARK III EOS-1 DS Instruction Manual page 161

C.Fn I -10
Disable: All the metering modes (q: Evaluative, w: Partial, r: Spot,
e: Center-weighted average) will be selectable.
Enable: Only the metering modes set with [Register] will be selectable.
Register: To make a metering mode unselectable, uncheck the checkmark
<X>. After entering the settings, select [Apply].
C.Fn I -11
You can set the metering mode to be used in the manual exposure mode.
0: Specified metering mode
1: Evaluative metering
2: Partial metering
3: Spot metering
4: Center-weighted average
With settings 1 to 4, you cannot change the metering mode by pressing the
<Q> button during shooting.
C.Fn I -12
Disable: The settable shutter speed range will be 1/8000 sec. to 30 sec.
Enable: The settable shutter speed will range from the highest shutter
speed to the lowest shutter speed set with [Register].
Register: The highest shutter speed can be registered within 1/8000 sec.
to 1/250 sec., and the lowest shutter speed can be registered
within 30 sec. to 1/60 sec. After entering the settings, select
[Apply].
C.Fn I -13
Disable: The settable aperture will range from the camera-attached lens'
maximum aperture to minimum aperture.
Enable: The settable aperture will range from the smallest to largest
aperture set with [Register].
Register: The smallest aperture can be registered within f/1.4 to f/91, and
the largest aperture can be registered within f/1.0 to f/64. After
entering the settings, select [Apply].
Select usable metering modes
Exposure mode in manual exposure
Set shutter speed range
Set aperture value range
3 Custom Function Settings
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