Canon EOS 60D Instruction Manual page 259

C.Fn IV -4
If you change the focusing screen, change this setting to match the
focusing screen type. This is to obtain the standard exposure.
0: Ef-A
1: Ef-D
2: Ef-S
About focusing screen characteristics
Ef-A: Standard Precision Matte
Standard focusing screen which comes with the camera. It
provides a good balance between viewfinder brightness and
manual focusing ease.
Ef-D: Precision Matte with Grid
Grid lines are added to the Ef-A
focusing screen. The grid helps to
align the shot vertically and
horizontally.
Ef-S: Super Precision Matte
The point of focus is easier to distinguish than with the Ef-A
focusing screen. Helpful to users who often focus manually.
About Super Precision Matte Ef-S and Maximum Lens Aperture
This focusing screen is optimized for f/2.8 and faster lenses.
With lenses slower than f/2.8, the viewfinder will look darker than with the
Ef-A focusing screen.
Even if you clear all the Custom Function settings to the default settings,
the C.Fn IV -4 setting will be retained.
Since the EOS 60D's standard focusing screen is the Ef-A, C.Fn IV -4-0
is set upon factory shipment.
To change the focusing screen, refer to the instructions that come with
the focusing screen. If the focusing screen does not come down with the
holder, tilt the camera forward.
The C.Fn IV -4 will not be included in the Camera user setting registered
(p.262).
Focusing Screen
3 Custom Function SettingsN
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