8. Autofocus measuring flash
The integrated AF red-light beam of the mecablitz
supports the automatic focusing of autofocus TTL
cameras. When the prevailing light is insufficient
for automatic focusing, the mecablitz will project a
pattern of red vertical stripes onto the subject as
soon as the camera’s release is lightly touched (or
is activated by the eye-start system of cameras of
the xi series). The camera’s autofocus system
then focuses the picture by this striped pattern.
Notes:
• When the camera’s autofocus system is on, the
electronic circuit will automatically activate the
autofocus measuring flash whenever the
prevailing light is insufficient for the exposure.
• Depending on the prevailing ambient light, either
the AF illuminator of the camera or that of the
flashgun will be activated whenever the autofo-
cus measuring facility becomes necessary.
• The range of the autofocus measuring flash
depends on the speed of the lens (maximum
aperture)! With an f/1.8 standard lens of 50 mm
focal length, the range is approx. 6-10 m (depen-
ding on the sensitivity of the camera’s AF sensor).
•
Only the central AF sensor is supported
Low-speed lenses,
e.g. with an aperture of
f/5.6 or f/8 (such as zoom lenses)
, significant-
ly restrict the range of the autofocus
measuring flash!
13
Fig. 5: AF red-light beam
AF red-light beam
