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Index
Preset
Aperture
Incoming light and depth -of-field are adjusted by turning
the preset aperture ring to the desired
f/
stop_
• As the
f/
stop value gets larger, the amount of light
reaching the film plane becomes correspondingly less
_
For each
f/
stop up, the light is reduced one
-half_
Accord-
ingly,
when the aperture is increased by one f /stop, the
exposure is doubled
,
and when it is increased by two
f/
stops the exposure is quadrupled
_
• Certain lenses, however, have no relation to the light-
ness being halved between the ma ximum and the next
f/
stops on the preset aperture ring
_
• The preset aperture ring can also be set between two
f/stops_
• The ratio between the aperture and the amount of
exposure
,
using
f/
2 as the basis
,
is as follows
:
f/stop
:
1.2 1.4
1.8 2 2
_
8 3 _5 4
5
_
6
8
11
16
22
Exposure Ratio
:
3
2
1.25 1 1/2 1/3 1/4 1/8
1/
16 1/32 1/64
1/
128
Presetting Aperture and Checking Depth-of-
Field
Lens with A-M Ring
1
Presetting of Aperture:
Set the A-M ring at
"
A"_
Then set the desired
f/
stop on the pre -set aperture
r ing to the index_ The diaphragm will close down to the
preset
f/
stop only for the instant that the shutter is re-
leased_
Except for that
instant,
the diaphragm remains
fully open_
13
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