F2: Assign Ae-L/Af-L Button; F3: Reverse Dial Rotation; F4: Slot Empty Release Lock; F5: Reverse Indicators - Nikon D5100 Reference Manual

f2: Assign AE-L/AF-L Button

Choose the role played by the AE-L/AF-L button.
Option
Focus and exposure lock while the AE-L/AF-L button is
AE/AF
B
lock pressed.
AE lock
C
Exposure locks while the AE-L/AF-L button is pressed.
only
AF lock
F
Focus locks while the AE-L/AF-L button is pressed.
only
Exposure locks when the AE-L/AF-L button is pressed, and
AE lock
E
remains locked until the button is pressed a second time
(Hold)
or the exposure meters turn off.
The AE-L/AF-L button initiates autofocus. The shutter-
A AF-ON
release button can not be used to focus.

f3: Reverse Dial Rotation

Select Yes to reverse the rotation of the command dial.

f4: Slot Empty Release Lock

Selecting Enable release allows the shutter to be released when no memory card is
inserted, although no pictures will be recorded (they will however be displayed in the
monitor in demo mode). If Release locked is selected, the shutter-release button is
only enabled when a memory card is inserted in the camera.

f5: Reverse Indicators

L
At the default setting of
viewfinder and information display are displayed with positive values on the left and
negative values on the right. Select
values on the left and positive values on the right.
166
G button
Description
G button
G button
G button
(V), the exposure indicators in the
A Custom Settings menu
AE-L/AF-L button
A Custom Settings menu
A Custom Settings menu
A Custom Settings menu
(W) to display negative