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Reproduced for Historical & Reference purposes by Paul M. Provencher -
http://whitemetal.com
16
Range of light measurement
The exposure meter of the Spotmatic measures the brightness of the ground glass. Therefore, the meter should be turned
on after you have focused your subject on the ground glass. The following table shows the range of the meter's light
measurement, and should not be interpreted as the camera's total range of f/stop-shutter speed combinations. As you will
note from the table below, with an ASA100 film, you may use any shutter speed from 1 sec. to 1/1000 sec. in combination with
any aperture that will bring the meter needle to the midpoint in the viewfinder. The total range of the aperture settings is, of
course, determined by the minimum and maximum apertures of the lens being used. For example, with the 50mm f/1.4 lens
and ASA 100 film, an aperture from f/1.4 (the maximum aperture of this lens) to f/16 (the minimum aperture) may be used
with any shutter speed from 1 sec. to 1/1000 sec. that will bring the meter needle to midpoint.
ASA B 1 1
/2
1
/4
1
/8
1
/15
1
/30
1
/60
1
/125
1
/250
1
/500
1
/1000
20
• 25
32
• 40
• 50
64
• 80
100
• 125
• 160
200
A
• 250
• 320
400
• 500
• 640
800
• 1000
• 1250
1600
• 2000
• 2500
B
3200
The area A indicates the reading range of the meter. The area B indicates that although the shutter speed index is black and
the meter needle moves, the meter is NOT operating properly.
When the meter needle is centered with the shutter speed dial set at B using ASA 20~50 films, this indicates that the exact
shutter speed required is 2 seconds. Please expose your picture for 2 seconds.