- TECHNICAL
INFORMATION-contlnued-------
-----"
EV
Range
of
the
Camera
What is EV?
Exposure value (EV)
is
a number representing the
available combinations of shutter speed and aperture
that give the same exposure when the scene bright-
ness and ASAIISO remain the same.
At
ASAIISO 100, the combination of a one-second
shutter speed and
an
aperture of f/1.4 is defined as
EV
1. If the lens diaphragm
is
stopped down by one
full f
ls
top or the shutter speed
is
one step faster, the
'
EV
increases by one ; if the aperture
is
one full flstop
wider or the shutter speed
is
one step slower,
EV
decreases by one. Using
ASA/I.SO
100
as
an
example,
1 sec. at f
/2
represents
EV
2, 1 sec. at f/5.6 represents
EY
5, while 1/125sec. at f/5.6 represents
EV
12
. Be-
cause the ex
po
sure is the same, 1/30sec. at
f/11
and
1/1000 sec. at fl 2 are
al
so
EV
12
.
36
EV range
The camera's meter may
be
used only within the
meter's
EV
range which determines the poss
ibl
e
combinations of aperture and shutter speed, depend-
ing
on
the film speed
in
use.
Fo
r example, at
ASA
/
ISO
100
, the FG-20's metering range
is
from
EV
1 to
EV
18
with
an
fl1.4 lens.
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