User manual
STOP
OPENINGS
Stop
openings
regulate
the
amount
of
ligh t passing
through
the lens.
These
openings
are
enlarged
or
reduced
by mov-
ing the lever
B,
see
page
10.
A knowledge
of
the
comparative
values
of the stop openings
is
necessary for cor-
rectly
timing
exposures.
The
stop openings
are
marked
].2.8,
4,
5.6, 8,
II
and
16. Besides these
apertures
the
Kodak
Retina
II
with
the
Xenon].2.0
Anastigmat
Lens has
the
marking
].2.0
.
This
opening
(J.2.0) allows twice as
much
light to
enter
the
camera
as J.2.8;
]'2.8
twice as
much
light
as].4,
etc.
Each
smaller
opening
(larger
number)
admits
half
the light
of
the
preceding
larger
stop opening.
Thus
, if
the
correct
exposure
is
1/ 100 second
at].5.6,
then
for
the
other
stop openings
the
exposure
should be
approximately:
].8
and
1/50;
f.11
and
1/25 second.
The
exposure for
the
average
outdoor
subject,
when
the
sun
is
shining,
is
].5.6
and
1/ 100 second.
If
the
day
is
hazy
or
slightly cloudy, use the
next
larger
open-
ing,
that
is].4
and
1/ 100 second.
In
this
way you will give twice the
normal
expo-
sure.
If
the
day
is
exceptionally
hrilliant
12