TTL ﬂash control | Metz 34 AF-3 P manual

5. TTL ﬂash control

The mecablitz receives its information exclusively from the connected TTL-controlled AF-camera.

Exposure measurement in TTL mode (TTL = through-the-lens) is completed by the camera’s sensor. This sensor measures the light reaching the ﬁlm through the camera lens. An electronic control circuit within the camera transmits a stop signal to the ﬂashgun as soon as the ﬁlm has been exposed by the correct amount of light; the ﬂash is then instantly cut out.

The advantage of the TTL mode is that all factors inﬂuencing the exposure of the ﬁlm (such as ﬁl- ters, change of aperture or variable aperture zooms) are taken into account. You need not worry about adjustment of the light output. The camera’s electronic system automatically deﬁnes the requi- red amount of light. You can also utilize various metering facilities (e.g. spot , matrix or centre- weighted overall readings) offered by some came- ras.

The table on page 33 gives the maximum range for the selected aperture. The minimum lighting distance is approx. 15% of the maximum thres- hold range.

If the actual distance is shorter than the minimum lighting distance, then this may result in overexposure.

The speed of ﬁlms to be exposed under TTL ﬂash control must be between ISO 25/15°* and ISO 1000/31°. Correct expo- sures cannot be guaranteed with other ﬁlm speeds.

A strip of ﬁlm must be loaded in the camera if tests are to be conducted in TTL ﬂash mode. The effec- tive ﬂash range can only be checked by the cor- rect-exposure display (o.k.) if the ﬂash is triggered by the camera and not with the manual release on the ﬂashgun!

*With automatic ﬁlm speed setting (DX): ISO 32/16°