How Light Modifiers Work

The most important criteria for evaluating and selecting small light modifiers is LOGIC.  It is important, and relatively simple, to understand how the flash diffuser is modifying the light and affecting the scene.

A primary objective in modifying the light from a photographic flash is to soften the shadows.  The overwhelming factor determining the “softness” of a shadow is the SIZE of the light source.  All things being equal including the light to subject distance, the larger the light source, the softer the shadows.   Since the photographic flash is a SMALL, high intensity source of light, it produces generally harsh, unattractive shadows.

How do flash diffusers soften the light?

Flash diffusers soften shadows by either refracting the light through a translucent material or bouncing the light off another surface, or some combination of the two.

If you refract the light through a translucent material, that material becomes the new and larger light source. The SIZE of that light source will determine the “softness” of the shadows. (i.e. softboxes and shoot-through umbrellas).

If you bounce the light off a nearby surface, that surface becomes the new and larger light source.  Select bounce surfaces and flash direction remembering that the angle of incidence equals the angle of reflection.Once again, it is the SIZE of that new light source that determines the“softness” of the shadows (i.e. bounce cards, walls, ceilings and umbrellas).


softens shadows because a larger light source produces a more gradual transition between deep shadow and full illumination.

THE most common misconception is that spreading the light over a wider area will soften the shadows. This is NOT the case. You must actually enlarge the light source to soften the shadows.

Small Light Source
Medium Light Source
Large Light Source



If the photographer can enlarge the light source and have it coming from a more natural direction, it will be a significant improvement over direct flash. All of our bounce and diffusion devices enlarge the light source and, at least to some degree, move it farther from the camera.

Our Quik Bounce incorporates ceiling bounce into the process by bouncing 80% of the light off the ceiling which becomes a new, larger light source coming from a more natural direction. The 20% fill is then directed back into the subject to help fill shadows cast by the ceiling bounce. The Quik Bounce is also designed with doors so that you can still enlarge the light for better images even if there's no ceiling to bounce off.



Accessories such as our UltraBounce are not shadow softening devices themselves since they are not materially larger than the flash itself. These accessories are actually light distribution devices.

By spreading the light over 180° it can be bounced back into the frame by nearby walls and ceilings. In relatively small rooms they are very effective at providing soft, even illumination. However, if used in large rooms or outdoors they have virtually no impact on shadow softness. Obviously it is pointless to illuminate 100° more than you are photographing if there are no surfaces to bounce the light back into the frame.

Spreading the light wider than the scene being photographed results in SUBSTANTIAL light loss  
There are nearby surfaces (walls/ceiling) to bounce the light back into the scene.  

The key is to use the right accessory for the situation and objective. Keep in mind that this is not magic; the road to softer more natural light is a larger light source coming from a more natural direction.


On often overlooked aspect in photography is color balancing the light, go in-depth on balancing light here.  Every light source has a different warmth or color.  Our eyes adjust to see white as a true white but the camera cannot tell, and if you mix multiple colors it can affect the image in a negative way.  

Using gels like the LumiQuest FXtra kit will let you balance the light to the ambient light in the room.  Warm color gels will help you balance incandescent lights, and green gels will help with fluorescent.  Making an image very cold (setting your white balance to a low K (Kelvin) number and then placing a very warm source on your flash will give you the Sports Illustrated look if you shoot outside.


For over 30 years LumiQuest has offered accessories of a variety of sizes to suit your needs. LumiQuest speedlight modifiers are not intended to replace larger umbrellas and softboxes. They do, however, bridge the gap between those devices and direct flash, especially when portability is a priority. However, when used in conjunction with “found” surfaces on location such as nearby walls and ceilings...the possibilities are endless.

Our devices fold flat for storage and are designed to minimize light loss. We have always offered and will continue to offer an unconditional guarantee. If you are not entirely satisfied with a LumiQuest product, simply return it for replacement or refund. Yes, that’s how well they work.

View our tutorial videos for more information on our most popular models.