Meter Sensitivity; Low Light Levels; General Information On Exposure Metering - Leica M6 TTL Instructions Manual

Meter sensitivity
The light metering range beg ins at 0.03
cd/m2 The working range at ISO 100/21 0
extends from -2 to 20 EV (exposure value),
i.e. from 4 s (shutter speed dial position "8")
at f/1 to
1/1
OOOs at f/32 (see also diagram on
page 29) .
Very low light levels
Should the light level fall below the range of
the exposure meter, the left t ri angular LEO
flashes.
Since the meter uses the working aperture,
the LEOs may also flash when the lens is
stopped down.
The exposure meter rema ins on for approxi-
mately 12 seconds after finger pressure is
removed from the shutter re lease button,
even if the light level is below the threshold
sensitivity level . If the light level improves
during this time (e.g. if the composition is
changed or the aperture opened), the LEOs
stop flashing and come on permanently.
26
General information on exposure
metering
Most scenes con tain an even dist ribution of
bright and dark subject details and refl ect an
average of 18% of the light fa lling on them .
This value of 18% corresponds to an aver-
age grey tone to which exposure meters are
calibrated. Ve ry bright subjects, such as
snow-laden w inter scenes, sa ndy beaches,
wh itewashed wa ll s or a wh ite wedding
gown, reflect more light toward the exposu-
re meter, tending to result in underexposure.
Predominantly dark subjects such as a black
steam locomotive, dark grey slate roofs, and
navy-blue uniforms refl ect much less light,
and meters te nd to overexpose . To achieve
correct exposures in these cases, the mea-
sured values must be corrected, unless
exposure is meas ured selective ly by inclusi-
on of only a portion containing a representa-
t ive sampli ng of dark and light subject
details. You wou ld for example meter on the
bride 's face and not on her white gown . A
landscape shot with a w ide-angle lens
should be metered with the LEICA M6 TTL
pointing downward to exclude the bri ght
sky.
When no such metering alternative is ava il a-
ble, a compensation factor of 2x or 4x can