Canon 199 A - Manual (Page 20)

The guide number of the electronic flash unit
changes with the speed of the film to be used.
Therefore, be sure not to overlook setting
the film speed on the flash unit as otherwise
proper exposure cannot be obtained.
The guide number calculation takes into
account ISO/ASA film speed set on the 199A,
i.e. the ISO/ASA setting on the camera. Please
make sure to set the ISO/ASA film speed
correctly on the 199A as otherwise incorrect
exposure will result for flash as well as non­
flash photography. Turn the ISO/ASA film
speed set dial whUe slightly pressing down on
it. Set the orange index line to the speed of
the füm to be used. The aperture display will
also change by changing the dial setting.
Setting of f/Stop * *
The setting of the f/stop, together with the
setting of the film speed, is a necessary step
for automatic flash photography.
Slide the flash control aperture selector
switch and display either red, green or yellow
in the display window. The ‘A’ mark is seen
below the switch.
* When the switch is turned to the lowest
end, white appears in the display window.
This means manual and pictures cannot
be taken in automatic mode. The ‘M’
mark appears above the switch.
Film Speed Setting
18