Olympus IS-1 - Manual (Page 60)

Measuring the amount of light
Light metering
Light metering refers to measuring the brightness
of certain parts of a picture. The IS -1 employs
three meterings: (1) ESP light metering, (2) center-
weighted average light metering, and (3) spot
metering. According to your photographic
purpose, the IS-1 allows you to select that which
is the most suitable.
At the same time, the IS-1 uses TTL (through
the lens) light metering to automatically measure
the light that enters the lens. This allows you to
obtain very accurate light metering without any
influence due to distance changes between the
subject and the camera.
ESP (Electro Selective Pattern) light metering
(Exposure mode P)
ESP light metering measures the central portion
and peripheral portion of the frame separately.
In doing so, the camera determines the proper
exposure. The calculation processing program
itself is based on trial and error data to properly
compensate for backlighting. ESP light metering
takes place automatically while in P (Program)
mode.
Center-weighted average light metering
Center-weighted average light metering is the
most widely used light metering system (Fig. A).
This system measures light within a wide range
with special emphasis on conditions in the center
of the picture. When in A (Aperture-preferred) or
M (Manual) mode, this light metering system
is automatically activated. Providing that differing
contrast between brightness and darkness in the
rest of the frame is not too
extreme (a portrait with an
extremely bright background
for example) the system
provides excellent results.
Spot metering
Spot metering (Fig. B) measures the brightness in
the central section of the frame only. Because this
metering system calculates the correct exposure of
one point, it is convenient when the subject is
backlit or there is strong contrast in the picture.
When shooting a subject in front of an extremely
bright background, you should spot meter the
subjects face. To make white objects look very white,
use spot metering and then operate exposure
compensation button in the (+) direction.
To make black objects
look very black, use
spot metering and then
operate the exposure
compensation button in
the (-) direction.
— 59 —