Olympus Pen FT - Through-The-Lens (TTL) Metering System; Understanding TTL Metering Operation

12 Through·The·Lens photometer:
• Through-The-Lens Metering System
S.ml.,,,,, •• ,,,,, mirr or
17
• P. hotometer indication window
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The Through ·The·Lens system to meas·
ure the amount of light passing through
the takin g lens operates in two different
ways; the open aperture and stopped ·
down aperture methods . The Olympus
Pen FT per mits applyin g either the " open
aperture" or the " stopped· down aperture"
method with the same lens and moreover
completely compensates for all measure·
ment errors talked a bout on conventional
Through ·The·Lens system cameras. It
represents th e most advanced Through ·
The·Lens system ever developed in the
world. Looking throu gh the. viewfinder ,
you see the
photometer in·
dication win ·
dow at the left
hand . The win·
dow carries
8
a series of
1if' Through · The ·
1::7 Lens numbers
from 0 to 7.
These
num ·
bers enable
you to deter ·
mine the cor "
rect exposu re
with ease.