Metz 34 AF-3M operating instructions Autofocus measuring flash, AF red-light beam

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

AF red-light beam

Fig. 5: AF red-light beam

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!

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