Canon A-1 - Manual (Page 154)

3. Manual Flash Control with Canon Speed-
lite 155A, 177A or 199A
The flash is on Manual and the aperture is
determined by a guide number calculation
and then set manually on the lens aperture
ring. The digital readout will include shutter
speed, “F” flash signal and the “M” signal
for manual aperture control. No aperture
data will be displayed. When the flash is set
to Manual, the viewfinder will display “M"
even if an FD lens is at the “A ” mark.
E D
M
4. Long Exposures with Canon Speedlites
133A, 155A, 177A and 199A
When the shutter speed is at “B”, the shutter
speed data in the digital readout will be
replaced by “bu” for “bulb”. The remaining
information as well as exposure warnings
remain the same as in each of the above
three cases.
For example:
1) AE Flash
U
E . B