Canon 540EZ - Manual (Page 23)

IV. Flash Operation in Various Shooting Modes
TTL automatic flash photography is possible in any shooting mode. Just
mount the 540EZ on the camera and select the desired shooting mode.
When the camera is set to aperture-priority AE
(Av), shutter-priority AE
(Tv) or manual exposure (M) mode, the 540EZ automatically operates in
TTL automatic flash mode.
® When the shutter button is pressed halfway, the camera sets the
shutter speed or aperture value in the same way as during normal AE
(non-flash) shooting.
• Depending on the shooting mode, the shutter speed and aperture vaiue are
set as foiiows:
EOS shooting mode Shutter speed Aperture value
P, Full Auto mode Set automatically (1/60 -- 1/X sec ) Set automatically
Av (Aperture-priority AE) Set automatically (30 sec. ~ 1/X sec) Set manually
Tv (Shutter-priority AE) Set manually (30 sec. ~ 1/X sec.) Set automatically
M (Manual exposure) Set manually (30 sec. - 1/X sec.) Set manually
• Set manuaiiy: Set by you
Set automaticaiiy: Automaticaiiy set by camera.
• 1/X sec.: Camera’s fastest fiash-synchronizing shutter speed (X-sync
speed)
When the shutter is pressed completely, the flash fires and the pic­
ture is taken. The flash output is controlled by the TTL automatic
flash program based on the aperture value set in ®. (During TTL
automatic flash control, the camera meters the flash light reflected
from the film during the exposure, and automatically slops the flash
when the proper exposure is achieved.)
The background exposure is determined by the shutter speed and
aperture value combination, just as in normal (non-flash) shooting.
TTL automatic flash is available in aperture-priority AE (Av), shutter-
priority AE (Tv) and manual exposure (M) modes.