The built-in flash is not powerful to reach distant background and shed light on to dark shadows. This Flashmate remote slave could be very helpful in solving these dark shadows and murky background problems.
This Cobra Flashmate remote flash is small with a size of 7×6.5×2cm and only uses one AA battery. You can put this slave unit on a table, shelf, window edge or any other convenience place and use its folding stand to aim the Flashmate where some extra light is needed. As a result, you can use this unit to soften background shadows, brighten areas out of the range of the built-in flash, and add some accent lighting on your subject.
The guide number, GN, of this unit is 10m (or 32ft) at ISO 100.
This is a slave unit. More precisely, it is activated by the built-in flash or any other flash unit. In other word, there has to be a flash that is controlled by the camera to activate a flash unit. The light sensor on the front surface of this unit will detect the flash light coming out from the main unit (i.e., the built-in flash or a flash that is controlled by the camera) and fire this remote unit. As a result, even though theoretically this remote unit can be placed anywhere, you must make sure the light sensor can pick up the flash light from the main unit. So, a few tests before actual shooting are required.
Please keep in mind that while the camera's exposure metering system can control the built-in flash for proper exposure, the camera's metering system measure the light intensity generated by this slave unit. The reason is simple. The built-in flash fires twice. The first flash is used for determining the correct exposure, and the second flash is for taking photograph. Slave units are designed to synchronize the second flash. As a result, the camera's metering system does not factor in the light generated by slave units.