ALPA 10d - Battery Change; Filter Factors

4) Range of CdS Meter System
Film speeds
Range of
ASA DIN Shutter Speeds
fastest
slowest
3
6
1/60
second
6 9
1/125
»
12 12
1/250
»
25
15
1/500
»
50 18
1/1000
»
100
21
1/1000
1/2
»
200
24
1/1000
1/4
»
400
27
1/1000
1/8
»
800
30
1/1000 1/15
»
Fig. 15
1600 33
1/1000 1/30
»
3200 36
1/1000
1/60 »
6400 39 1/1000 1/125 分
If the speed required is outside these
ranges ， the correct setting can be easily
determined ， as the ASA film speed
ratings are directlγproportional to the
shutter speeds and f/stops (with the
exception of the maximum apertures on
certain lenses).
Example: You wish to take a picture
with an ASA 12 film at a shutter speed
of 1/1000 second. The fastest possible
shutter speed is 1/500 second. Assum-
ing the correct f/stop with 1/500 second
is f/5.6 ， γou simplγopen the aperture to
f/4 and set the shutter speed to the
desired 1/1000 second.
If the shutter speed exceeds 1 second ，
γou can easilγdetermine the exposure
based on the ASA film speed rating.
Example: You wish to take a picture
with a 25 ASA film. The lens is set at
full aperture and the shutter speed at
1 second ， but the needle still cannot be
centered. Change the ASA setting on
your dial until the needle is centered.
Assuming that it indicates 100 ASA ， i.e.
2 stops above γour film speed of 25
AS A， yo u easiIγdetermine the exact
shutter speed of 4 seconds.
5) Battery Change
If the needle no longer moves ， while
you depress the release button ， the
batteries have to be changed. Make sure
there is no film inside your ALPA 一
(counter must be 3 numbers below 0 ，
see page 6)-and remove the camera
back. Unscrew the large lid of the bat-
tery housing at the bottom with a coin.
Insert 2 new standard Mallory Mercury
PX 450 batteries ， both with the + sign
facing outwards i. e. towards the camera
bottom (Fig. 15).
6) Filter Factors
Exposure factors caused by filters are
automatically compensated for bγthe
behind-the-Iens CdS meter system ，
except for certain red filters.
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