Canon EOS 30D Instruction Manual page 91

If the exposure level mark <s> blinks at the <G> or <F> level, it indicates
that the exposure level exceeds the standard exposure by ±2 stops.
Set the exposure.
5
Check the exposure level and set the
desired shutter speed and aperture.
Take the picture.
6
a Manual Exposure
: Standard exposure level.
: To set it to the standard
exposure level, set a
slower shutter speed or a
larger aperture.
: To set it to the standard
exposure level, set a
faster shutter speed or a
smaller aperture.
91