Lighting Techniques

Five great reasons to use an external flash

Written by Digicamhelp Editor

If your digital camera has a hot shoe, it can accept an external flash. Here are five compelling reasons to use one.

Bounce flash used

Photo taken by bouncing an external flash. It looks more natural due to the soft light. It lacks harsh shadows, a frequent undesirable affect when using a built-in flash. Click to enlarge.

Many advanced compact digital cameras and all digital single lens reflex cameras are capable of using an external flash. An external flash can be one of the most useful accessories when taking photos in less than desireable light.

If your camera has a hot shoe, it will accept an accessory flash. Here are five top reasons to use one.

Less likely to create “red eye”

Red eye is caused by the flash reflecting off of the lining of the inside of the eye. It is more likely to happen if the flash is close to the lens of the camera. Most built-in flashes have a “redeye reduction setting. This attempts to constrict the pupil to reduce the effect of redeye but can’t over come it completely.

The external flash is usually higher up and this helps some but you can also bounce the light to eliminate redeye completely. You can also use an accessory cord to move the flash away from the lense axis.

Bounce flash

Can you tell which image was taken using a bounce flash?

Can you tell which image was taken using a bounce flash? Photo illustration by James Jordan.

Most external flashes have the ability to tilt and or swivel the flash head. If you have a low white ceiling the flash head can be pointed up to direct light to the ceiling then back down to the subject of the photo. This works pretty well as we expect to see light coming down from above and it eliminates red eye. You can also bounce light off of a near by white wall for a nice sidelight look.

Just remember that the further away the ceiling or wall is the more power will be needed. Remember, too, that the flash takes on the color of what ever it hits.

More power

The built-in flash in a compact or DSLR camera is nowhere near as strong as a good external unit.  This means an external flash will be effective at ranges the built-in flash couldn’t hope to match.

Flash power is usually expressed as GN (guide number) this is supposed to indicate the distance in meters at which the flash is effective. The built-in flash likely has a 10GN where as most external flashes start at least at GN42

More options, more toys

Depending on the flash and camera manufacture, you may be able to control the flash while it is off of the camera.  Nikon refers to this as CLS (creative lighting system) Canon calls it wireless ETTL. This allows for using the flash from a different angle or for using multiple flashes for studio style lighting.

As with all photographic items, there are accessories for the accessories. You can get extenders to increase the range of the flash, gels to change the color, diffusers to scatter, bounce card and soft boxes/umbrellas to soften, grids and barndoors to restrict and shape the light.

Best reason to get an external flash: creativity

The more power, control and options you have the more you can experiment and learn to do something cool with your camera.


  • Gail’s suggestion will work if there is only one color of light but if you are using flash in addition to whatever light was in the room then there are 2 colors of light and the camera can’t compensate for both at the same time. The short answer is that you have to either get rid of one of the light sources (ie use just existing light or just flash) or change the light from the flash to be the same color as the room lights. I will be posting an article on how to do this very soon.

  • Margaret, thanks for you kind words. Glad you find the information helpful. I’m assuming you are using a DSLR with an external flash.

    Use the closet white balance preset to the type of lights in the room. Or try the FLASH white balance setting.

    Better yet, do a custom white balance, which is relatively easy on many digital cameras and instructions are outlined in the manual. If you don’t have a white balance card, do a custom white balance using a piece of white paper or something as simple as the underside of a white, translucent coffee can lid.

    Always take a few test shots and check the LCD to see if the color balance is satisfactory. Shoot RAW, or RAW+JPEG, to. White balance in RAW files can be easily be adjusted when processing the files.

  • Hello,
    I find your articles very helpful – thank you for a great source of information.
    Question:  When taking a picture picture inside a house (internal real estate) when I am in a basment with limited light source and have to use flash how does that affect my WB.  (ie light in the basment are pot light)
    please advise – thank you