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10. SETTING THE DIAPHRAGM
The diaphragm
ring is marked with white figu-
res ranging from 1.8 to 16 for a F /1.8 lens and
fron 2 to 16 for a F /2 lens. Turn the diaphragm
ring so that the desired aperture figure (white)
may coincide with the white dot.
. T h e d i a p h r a g m
r i n g i s u s e d t o a d j u s t t h e l i g h t
volume and the depth of field (see P.33).
. You may use intermediate
aperture openings
between any two F/stops.
. The larger the aperture figure becomes,
the
less light volume is permitted
through the lens.
. T h e r e l a t i o n s b e t w e e n t h e a p e r t u r e a n d t h e
l i g h t v o l u m e a r e s h o w n i n t h e d i a g r a m s h o w n
a t t h e r i g h t . T h e l i g h t v o l u m e d e c r e a s e s
b y I / 2
for every one decrease
in the F figures. Expo-
s u r e c a n b e s e t t h r o u g h t h e c o m b i n a t i o n
b e .
t w e e n t h e a p e r t u r e o p e n i n g a n d t h e s h u t t e r
speed.
. W h e n e i t h e r t h e a p e r t u r e
o p e n i n g
o r t h e s h u t t e r
speed are shifted to their respective
next gra-
duations,
the light volume increases
by twice
or decreases
by I/2.
. T h e d i a p h r a g m
c a n b e s e t e i t h e r b e f o r e o r
a f t e r t u r n i n g t h e f i l m a d v a n c e
l e v e r .
A p e r t u r e
Lgh, ooo(}{}fr,?ap-
V O l U m g
? .
I
t / r
t / .
i j t
t / t .
r i z
20
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