The holy grail in flash photography is an image that flatters your subject without looking unnatural.
While flash introduces a myriad of issues, the five most common problems are unwanted strong cast shadows, unflattering emphasis of facial lines or wrinkles, blown out highlights especially on skin areas, shifts in color (notably in skin tones), and red-eye. A good flash diffuser can help you avoid such distracting elements in your composition by widening the apparent light source, dividing and/or spreading the light output for multiple purposes, coloring the light source where desired, and helping to mitigate red-eye while still producing the distinctive catch lights in your subjects eyes that make portrait shots really pop.
For most photographers, a good diffuser is a balance between cost, portability, ease of use, and its feature set. Diffusers come in a wide array of choices, each with its own merits. Choosing the right one largely depends on how you plan to use it. Many are designed to work with specific model flashes, others are more general purpose. Some are primarily designed to be used off-camera, but can also be used on-camera if you are aware of their limitations. We have selected the best of those diffusers that can be used with most on-camera flash units.
We have chosen the following five flash diffusers on the basis that they will fit on a wide range of camera mounted flashes, do an excellent job of diffusing light when operated per the manufacturers instructions, are easily portable, and can be used on-camera when needed, even if primarily intended for off-camera use.
This diffuser is great because it does not interfere with camera functions when used on-camera. It also provides a wide latitude for creating a custom light pattern that actually falls on your subject. Read Full Review
When it comes to shaping the light output of your flash, the ExpoImaging Rogue Flashbender provides the widest range of choices. Three bendable frame wires allow you to alter its reflector perimeter from a flat reflecting panel down to a narrow snoot. Turn it around and its black reverse side can be used as a flag to control unwanted stray light. The Rogues 6-ounce on-camera weight coupled with its 10-by-11-inch size is a consideration for run and gun shooting or if you need to use your flash at intermediate flash head angles, as the weight and its vector geometry will tend to force the flash head to one of its locking steps. For the same reason, it can make your camera somewhat top-heavy, making precise framing control a little difficult when shooting handheld.
The Rogue folds down flat for easy storage in your camera bag. It attaches snugly to your flash using a Velcro belt without the need to install adhesive patches on the flash itself. Additional mounting stability can be obtained by reinforcing the Velcro belt with a rubber band to tighten snugness.
This is a good choice when you need to evenly light larger groups. Plus it's particularly effective when used as an off-camera flash. Read Full Review
The Lumiquest Promax Softbox III is an excellent choice when you need to spread your flashs output to evenly cover larger groups, achieve maximum softness in cast shadows, or in situations where bounce light is simply not available. Spreading light does have a cost though; with the Softbox III, there is a 1.25 stop light loss. Its slightly over seven ounce weight introduces similar considerations for on-camera or run and gun usage as do other diffusers primarily designed for off-camera use. In addition, on some cameras, the Softbox IIIs profile extends down in front of the cameras auto exposure sensor and autofocus assist, which can interfere with these functions.
Out of the box, the Softbox III attaches by adhering Velcro strips to your flash unit. This can be easily avoided by obtaining a separate HONL Velcro strap. The Softbox III folds flat to 8-by-9 inches for easy storage.
This diffuser is also a good choice for evenly lighting larger groups when used either on or off-camera. Its lighter on-camera weight promotes improved stability, but can interfere with some of the camera's functions. Read Full Review
The Westcott Pocketbox Max offers much the same features as the Softbox III but at less than half the on-camera weight penalty. In addition, it comes with a second internal diffuser to further soften the light output, but at a cost of an additional stop of light loss. TTL will automatically compensate but the battery drain will be greater due to the increased demand in light output. Used on-camera, its 8-by-12-inch size also can interfere with the cameras auto exposure sensor and autofocus assist.
The Pocketbox Max folds flat to its 8-by-12-inch size for easy storage. Like most diffusers with this relatively large profile, it was primarily designed to be used off-camera. It can be used on-camera but can interfere with the cameras auto exposure sensor and autofocus assist and its mass can affect handheld camera stability.
This diffuser is particularly good in "run and gun" shooting situations. It can also be combined with a wide array of light modifier tools to accommodate a wide range of light shaping needs. Read Full Review
Gary Fong is a well-respected wedding and portrait photographer who, incorporating his experience, developed a flash diffuser that is widely endorsed by many for run and gun shooting such as weddings and event photography. He also offers videos at his website on how best to use his diffuser. Unlike earlier versions that were not collapsible and were dedicated to specific flash heads, this newest version is pretty universal and collapses to fit neatly into even a small camera bag. Its one-size-fits-all design lets you swap between flash heads and it wont become obsolete should you change flash heads or camera systems. The downside is that, because the diffuser is designed to fit the median flash head profile, it tends to be a little loose on some flashes meaning it might unexpectedly slip off your flash, and pretty snug on others which makes quick changes problematic in run and gun situations.
Gary Fong offers a range of light modifiers appropriate to event type photography that afford wide latitude in dealing with rapidly varying environments such as weddings or rope-lines.
Vello's Universal Bounce Diffuser is low cost, easy to use, portable, and light weight. It's an excellent choice for on-camera use where basic fill light will serve the purpose. Read Full Review
For an effective, low-cost, easy to carry diffuser, the Vello Universal Bounce Diffuser might be an excellent choice. Pull the stretch waistband over the top of your flash and youre ready to go, but it will take two hands to mount. The material on one side is black so you can turn the diffuser around to block light when needed. Its light weight means youll be easily able to shoot on-camera handheld without annoying camera top heaviness. The Vello Universal Diffuser folds flat for easy portability and is surprisingly well-constructed for its price category.