for Hot-Shoe Flash
There are many ways to diffuse a flash. The simplest is to simply tilt the flash head up and bounce the light off a low white ceiling. This tends to light up the entire room like an overcast day and if used too close to a person downward direction of the light can result in the brow shading the eye sockets. Indeed a well lit face with dark detailess eye sockets is one way to detect that ceiling bounce has been used.
Plastic cap devices solve the problem of dark eye sockets by bouncing about 80 percent of the light off the ceiling but allowing about 20 percent to be projected forward. The portion bounced off the ceiling lights up a large area with soft light just as direct flash bounced off the ceiling would.
The drawback of these two methods of diffusion is that absent a low white ceiling they are not very effective and even when there is a ceiling much of the flash power is wasted illuminating areas which are not in the photo. Also they offer the photographer very little creative control over the direction of the light or the lighting ratio on the subject's face. It is the placement of shadows and their lack of detail which make them distracting.
More consistent results can be obtained by bouncing the flash into a surface which stays attached to the flash. Bouncing into an umbrella produces soft directional light and is more efficient and controllabe than bounce, but the size of the umbrellas and the need for stands to hold them unsuitable for moble shooting.
I've used a pair of hotshoe flashes in a key / fill configuration for many years and have tried umbrellas and several DIY camera flash diffusers. I found that a bounce-card type diffuser offered the best combination of diffusion, directional control and portablility. The simplest form of this type of diffuser in literally an 8x10 white card attached the flash via velcro or a rubber band.
By folding the card into a bowl shape it is possible to capture all the light from the flash and bounce it forward, which wastes less light on non-image areas and is thus more efficient. The photo above shows the pair of reflection-diffusers I created with a couple pieces of white/black mat board, black masking tape and a few staples. Here's how the diffuser looked mounted on my off-camera flash:
A guy posting on the DPReview lighting forum posting under the name MikeM who had seem my refector took the same idea in a slightly different direction with a bounce reflector made of flexible sheets of stuff called "Fun Foam" which can be found at Walmart and craft stores. It had the advantage of being able to be folded flat for storage.
I switched to using Mike's design, with a couple of modifications; fewer slits, less velcro, and the use of a cross-stitch matrix also found at Walmart as an internal stiffener. Much easiler and faster to make:
The foam reflection diffuser is the same size and shape as the ones made out of mat board and function similarly. Here are shots taken with a single flash a Stroboframe Bracket using a 10mm lens on my D20 (a field of view is similar to a 17mm lens on a full-frame 35mm) which demonstrate the coverage and light quality with and without the reflection-diffuser.
Here's a self-portrait taken with a pair of flashes with diffusers:
Here are some unposed candid shots taken with the dual strobe set-up. While not on par with controlled studio lighting and softboxes the added dimensionality of short lighting and a softening of the light versus the results with a direct flash in the hot shoe is nothing short of remarkable IMHO.
A wide shot at 10mm with my Canon D20 just to show the light position and coverage. My lightstand has five wheels which made it easy to move. It's actually not a light stand, but something called a "Pitch-it"I found at a thrift store.
A medium shot to show the overall lighting pattern:
A H&S shot. I switched lenses to the 85mm and moved the light closer and slightly more behind her for this one.
These are just quick grab shots, but imagine all the candid shots at a wedding or other events you photograph with this quality of lighting. It is something which will set your work apart from other shooters who only use one light.
Templates showing dimensions
Inside: Click image below for full size template
Outside: Click image below for full size template
Mesh in the middle: Click image below for full size template
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