Pocket Digital Slave Adaptor

While Digital SLR's offer the best in terms of performance for professional photography, often times they aren't suited for everyone. Even as the price of declares continue to drop, and drop quite significantly, they still might not be the best alternative for many photographers, especially considering the price involved in when building a kit with enough lenses to handle all of the jobs that can be handled quite well with a regular 'quick and easy' pocket (non-slr) digital camera.

The exception to this rule however is generally flash photography, where pocket digital cameras generally lack the ability to play nice with external flash units. The problem is that on many cameras, there is no way to physically link the camera to the flash, so it's impossible to sych and external flash with the camera shutter. An alternative is to use a slave trigger, which fires an eternal flash when it 'senses' the flash burst from the primary flash. Slave flash is normally used in studio where multiple flashes are used, but without a physical wire being used to directly connect them. With slave flash it is possible to trigger an external flash when using a small digital camera.

The trouble arises however when you want to fire an off-camera external flash, but you don't want the direct flash comming from the camera itself to illuminate the subject. The trick is to find a way to trigger the slave flash units with the on-camera flash, but without letting the light from the on camera flash fall onto the subject.

The most common solution to this problem is to use a strip of developed (but unexpected) slide film to cover the flash on your digital camera. Most flash slave units are actually triggered by the infrared blast of a flash unit, rather than the visible light. Slide film is designed to block visible light, but to let IR pass through unimpeded. Hence, it makes the perfect filter to cover your flash.

What you'll need:

Developed, unexposed, Slide film.
Tape.
(Digital Camera)

You'll want to pry open the slide holder to extract the film on the inside.


Here I used a Nikon pocket digital camera. Really this camera is a bit too simple for this sort of photography as it's designed quite explicitly only as a snapshot camera with no ability to manually adjust exposure. But it serves as a nice example for this article.


You'll need to cut the strip of film to fit over the flash. Make sure not to cover any sensors. In this case I creased the film so that it fit a bit more snug.


Take the film down so that light doesn't escape from under the film.


And that's it, when you shoot don't use the red-eye mode, and avoid any special flash functions that might interfere with the slave flash. With a camera such as this one, which doesn't have the option to manual fire a single flash burst (instead it fires a 'pre-flash' to meter the scene) you'll need to get a special digital-slave flash adaptor, which ignores the first 'pre-flash' and triggers on the second burst instead.

Here's the flash in action, just a tad of visible light escapes.

Notes:

Some cameras (such as this one) will meter the scene based on the pre-flash. These cameras won't work well, if at all, with external slave flash as they will generally overexpose most scenes as they will meter on a scene without the light from the slave flash. If you own one of these cameras, don't give up hope. Just do a little trial and error to figure out how much light from your flash is just enough for your particular scene. But in general the best cameras for this hack are just above the novice level, and below prosumer. Enjoy!