Canon Powershot A450 Advanced User's Manual page 93

Before attaching the bracket to the flash, check that the
lithium battery (CR123A or DL123) is installed.
To illuminate the subjects properly, install the flash so that it
is up against the side of the camera and parallel with the
camera's front panel.
A tripod can be used even when the flash is attached.
Batteries
Charge becomes Severely Limited
If the battery usage time has considerably diminished, wipe the battery
terminals well with a dry cloth. The terminals may be dirty from fingerprints.
Usage in Cold Temperatures
Get a spare generic lithium battery (CR123A or DL123). You are
recommended to place the spare battery in your pocket to warm it
up before switching it for the battery in the flash.
Non-Use over Extended Periods
Leaving batteries in the High-Power Flash could allow the battery
fluid to leak, damaging the product. Remove the batteries from the
High-Power Flash and store them in a cool, dry place.
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