Slave Unit for Digital Cameras

This document last updated May 2006

The emergence of digital cameras causes a problem for photographers using conventional slave units, because many digital cameras issue a double flash pulse; the main flash being preceded by a 'pre-flash' to set the exposure level or colour balance. In principle it is fairly straightforward to modify my slave unit to fire on the second pulse it receives, or to fire after a pre-determined delay. The most economical way to alter the design is to add a small microprocessor. This opens up other possibilities - for example, a 'fired' indication becomes easy to add, as does a low battery warning. A new slave unit, designed to work with digital cameras, retains all the features of my existing slave, namely ...

• Very high sensitivity
• Infrared sensitive for use with "dark" flashguns
• Usable underwater
• Not sensitive to caplamp beams
• Not adversely affected by ambient light
• Triggered by, and will fire flashbulbs
• Compact design
• Low current consumption / long battery life

( details) and adds the following … ·

• Single pulse, multi-pulse and delayed-fire operating modes
• 'Learning mode' matches unit to different camera characteristics
• Fail-safe operation if fewer than expected flash pulses are detected
• A low battery indication
• Adjustable firing delay for use with cascaded units, and master/slave electronic guns
• LED to indicate that the unit has been triggered (useful for setting-up purposes)

Kits of parts are available (see Newsletter), and a fully-built version is available from Firefly Electronics