Camera Controls - Canon A-1 Repair Manual

f / 2 . 8. Because of this revision, take notice of the
following phenomena particular to this lens:
a) When you are in shutter speed priority mode, at
the 70 mm focal length selection the viewfinder
display flashes f/2.8 when the maximum aperture
is actually f/3.5.
When you are in aperture priority mode, at the
70 mm focal length selection, the viewfinder dis-
play indicates f/2.8 instead of f/3.5 when set to
the maximum aperture. (New lens; old lens may
s how either f/2.8 or f/3.5)
b) When you are in shutter speed priority mode, at
the 35 mm focal length selection, the viewfinder
display flashes f/3.5 when the aperture is set to
f/2.8.
When you are in aperture priority mode, at the
35 mm focal length selection, the viewfinder dis-
play may indicate f /3. 5 when the aperture is
preset to f/2.8. (old lens)
c) When you are in programmed AE mode, at maximum
aperture (AVO) t he aperture is fixed and the
shutter speed becomes variable. But, in this
case, the aperture value shifts a little bit,
also.
Combination use with the Motor Drive MA
With the "high" mode setting, the viewfinder display
is not visable.
With the "low" mode setting, the viewfinder display
is visible, but the flashing warnings cannot be seen.
However, depending on the battery consumption in the
Motor Drive MA the winding speed is not always the
same and, accordingly, the above description may not
be true at all times.
4.3 Camera Controls
(1) Control Block Diagram
All data received such as film speed, exposure method
(shutter speed in case of TV setting; f/stop value in
case of AV setting; P setting in case of programmed
exposure), maximum f/stop value of the lens in use,