Two readers have forwarded an announcement about a new "diffuser" for the pop-up flash by the maker of a line of popular modifiers for external flash units. This item is a curved, semi-opaque plastic device that situates in front of the pop-up flash so that light will pass through it and produce less glare. It appears to be about 2 inches tall and 4 inches wide. Another maker of external flash modifiers sells a 4x4" rectangular piece of semi-opaque paper that situates in front of the pop-up flash to soften the harsh light from the flash.

Either of these will, in fact, reduce glare on subjects close to the camera. They will NOT redirect the light to create a larger effective light source that evenly illuminates a large space. Nor will they cause light to emanate from a more natural direction. Bouncing is a far more effective way to diffuse light from the flash.

It's time to pull out one of my early posts on this subject, so if this seems familiar, please forgive me. On the other hand, I find as an educator that repetition is often necessary to reinforce important lessons.

• The softness of light results from the size of the light source in relation to the subject. While bouncing a strobe or using it with softboxes and similar flash accessories can effectively increase the size of a light source and thus nicely disperse and diffuse light over a relatively large area, a small diffuser placed in front of the pop-up flash cannot significantly enlarge the flash's tiny light source... so cannot evenly illuminate a scene for candid shooting

• The physics of light is that it falls off at the inverse square: Something near to the light source receives more light than something farther away. As the distance of from the flash doubles, the brightness reaching the is QUARTERED. The brightness is NOT half as bright, but only 1/4 as bright. Double the distance again, and the light is reduced to 1/16 the brightness. The first picture of my dentist provides a good example of the inverse square law at work.

He's lit, but his assistant is in the dark. Putting a small diffuser in front of the flash may soften the harshness of direct strobe somewhat but will not change the fall-off resulting from the inverse square law. With a small diffuser, people in the background remain in shadow.

• Putting a diffuser in front of a pop-up flash also does NOT change the unnatural direction of the light (aligned with your forehead... like my dentist's head lamp), which is another of the reasons direct flash is awful. (Some of the nicest results with the Lightscoop have come from using it to bounce off a wall — emulating window light. Betsy shot the picture of yours truly, above, bouncing the pop-up flash off a wall.)

In any case, I've designed the Lightscoop™ to REDIRECT the light from the tiny pop-up flash toward a ceiling or wall.

1. The light travels from the flash to Lightscoop's reflective surface and reflects the light up in a widening cone to the ceiling or out to a wall.
2. That reflected light bounces OFF the ceiling or wall and back onto the subject or the scene.
3. The ceiling or wall  thus effectively becomes a MUCH larger light source, reflecting light downward/outward.

Redirecting the pop-up flash

1. enlarges the effective light source,
2. diffuses the light,
3. sends light toward the subject from a more natural direction.

Of course, the ceiling must be light-colored and no more than 8-12 feet tall. Wall bounces work best when the camera is about 3-6 feet from the wall.

The pattern on the ceiling in my early  test shots demonstrates how much larger the effective light source has become when the light travels up to the ceiling reflects back down:


The drawn illustration, below, also shows the principle at work: