Canon 300 HS - Manual (Page 103)

103
You can lock the exposure or change it in 1/3 steps within a range of ±2
before shooting.
Focus.
∆ Press the shutter button halfway to focus.
Lock the exposure.
∆ After releasing the shutter button, press
the
o button to lock the exposure. The
exposure shift bar appears.
∆ Press the o button again to release the
lock.
Change the exposure.
∆ While watching the screen, turn the – dial
to adjust the brightness.
Shoot.
AE Lock/Exposure Shift