Replacing The Date/Time Battery - Canon EOS 5D Mark III Instruction Manual

Replacing the Date/Time Battery

The date/time (backup) battery maintains the camera's date and time.
Its service life is approx. 5 years. If the date/time is reset when camera
is turned on, follow the procedure below to replace the backup battery
with a new CR1616 lithium battery.
The date/time/zone setting will also be reset, so be sure to set the
correct date/time/zone (p.36).
For the date/time battery, be sure to use a CR1616 lithium battery.
1
Set the power switch to <2>.
2
Unscrew the battery holder
screw.
Use a small Phillips screwdriver.

Be careful not to lose the screw.

3
Take off the battery holder.
Push out the battery as shown by

arrow 2.
4
Replace the battery in the battery
holder.
Make sure the new battery is in the

proper + – orientation.
5
Tighten the battery holder's
screw.
343