Exposure Compensation Dial - Canon PowerShot G12 Basics Manual

Source: Canon PowerShot G12 Camera User's Guide
Automatic Exposure (AE) Lock
The camera's exposure settings can be temporarily locked by depressing
the AE Lock button. Once locked, the AE Lock symbol will appear in
the LCD viewfinder and will remain visible while you compose the shot.
Once the image is shot, the AE Lock is released, and the symbol
disappears from the viewfinder.
Auto Focus Frame Position and Size Button
In semi-automatic or manual shooting modes, press this button to move
or resize the focus frame. To move the frame, rotate the control dial or
press the up, down, left, or right positioning buttons. Press the DISP
button to make the frame smaller or larger.
In playback mode, press this button to erase the displayed image from the
memory card.
Light Metering Button
In semi-automatic or manual shooting modes, press this button to cycle
through one of three light metering methods:
• Evaluative metering – automatically adjusts exposure base on an
evaluation of the entire frame. Suitable for normal shooting
conditions.
• Center-weighted metering – averages the light metered from the
entire frame but gives greater weight to the center.
• Spot metering – only measures the AE point frame (typically set to
the center of the frame)
In playback mode, press this button to jump to images based on a chosen
filtering method.

Exposure Compensation Dial

In shooting modes where exposure compensation is allowed, this dial
can be set to decrease or increase the brightness of the image in 1/3-stop
increments across a range of -2 to 2. The photographer can use this
control to effectively override the camera's automatic exposure setting
to achieve a slightly darker or lighter image. Unless you intentionally
want to override the AE settings, its best to leave this set to 0.
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