5. TTL flash control
The mecablitz receives its information exclusively from the connected
Exposure measurement in TTL mode (TTL =
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 37 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-
*With automatic film speed setting (DX): ISO 32/16°
9