subject reflectivity measured TTL; based on this information, second (main) flash duration is calculated, and then strobe fires main flash quickly afterwards, only for the specified duration.
3)During exposure, strobe itself measures in real time
Using a light sensor in the strobe, subject reflectivity measured in real time, with strobe quenching at time of “proper” exposure. (External Auto Flash Exposure Adjustment)
For each of these automatic flash adjustment methods to work, besides a signal instructing the external strobe to fire, the various combinations of cameras (and master strobes) and external strobes must be compatible with each other’s signal transmission methods.
- In case of 1) above: | From Camera to External Strobe | Instruction to stop flash |
- In case of 2) above: | From Camera to External Strobe | Instruction to stop flash; or, |
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| Instruction for flash duration |
| External Strobe to Camera | External strobe information |
- In case of 3) above: | From Camera to External Strobe | ISO Sensitivity information, and |
|
| Aperture Value information |
As of December 2002, a majority of consumer digital cameras use
Because
The external strobe to camera signal transmission specifications have not been standardized between camera manufacturers, and the communication method used by most existing external strobes has not been adopted in most digital cameras.
Due to the lack of real time information from camera to strobe, digital cameras cannot automatically adjust exposure with external strobes. Therefore it is necessary for the external strobe itself, to a certain extent, independently execute automatic flash adjustment.
The
INON | 14 |
Version 1. October 4, 2003 |
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Copyright 2002, 2003 by INON America, Inc. | All rights reserved. |