Contax 159MM - Aperture Ring; Regulating Light and Depth of Field

The
aperture ring
regulates
the
amount of light
transmitted
to
the film
plane.
The
amount
of
light
transmission
is
halved
when the
aperture
is
changed to
the next larger
f
value
(for
example, when
f/4 is
changed
to f/5.6),
and
doubled
when it is
changed
to the next
smaller
f value.
The
aperture
also
controls the
depth of field,
a
lens
property
giving
you
varying
depth in the
plane
of focus
at
different apertures.
(Refer
to
page
102)
To
set the
aperture, turn
the
aperture ring
until the
desired
aperture
setting
is
aligned with
the
aperture/distance
scale
index.
The
aperture ring
can
be used
at
in-between
positions.
The minimum
aperture
setting of
"16"
is in
green
to
indicate
that
the lens
is
to
be
set at
this
position
in
the
34
Program
AE
mode.
The minimum
aperture
setting varies
with
the type
of
lens
in
use.
The
aperture can be
confirmed
using
the viewfinder
aperture display.
In the Program AE
mode,
the
camera-
selected aperture, and
in the Aperture-priority
AE
and
the
Manual modes, the
user-selected aperture,
as
well
as
intermediate values,
are displayed.
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