EXPOSURE
CONTROL-Continued
Lens
aperture
diaphragm
The Nikomat
ELW
can be used with any Nikkor
interchangeable
lens
with a
Nik
on F bayonet
mount. Except the reflex len
s,
these lenses are
eq
uipp
ed
with aperture diaphr
ag
ms,
and graduate d
with a stop by stop scale from f
ull
aperture to the
minimum stop number.
When
a Nikkor lens
is
mounted on to the camera,
it
is
designed to stay open at full aperture
even
when the aperture ring
is
turned down . The aper-
ture diaphragm
is
set only when the shutter button
is
snapped and the shutter curtain
is
opened. This
is
called the automatic diaphragm mechanism. The
diaphragm regulates the amount
of
light reaching
the film, while stopping down the aperture
by
one
graduation (from
F5
.6 to F8), cuts the amount
of
available light
in
half. Diaphragm openings also
have
a direct bearing on the depth
of
field. (Refer
to
page 47.)
42
Depth-of-field preview button
The depth-of
-f
ield
preview button lets you check
the depth
of
field before shooting to make any
desired adjustments.
Press
the button and the lens
stops down to the preselected aperture to allow
you to
see
how much background or foreground
is
in
or
out
of
focus.
* In
fullยท
aperture
measurement,
if
the
shutter
is
released
while
simultaneously
pressing
the
depth-of-field
preview
button,
the
correct
exposure
will
not
be
obtained
. Also,
do
not
operate
the
film advance lever
while pressing
the
button.
* When using
the
Auto
Winder A
W-l
do
not
snap
the
shutter
while pressing this
button
. If
you
do
so
by ac-
cident
, switch
the
A W-l
power
off
and
then
on
again to
restore normal
operation.
For detailed operation, refer
to
page
47.