When You Need an External Flash in Photography

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Occasionally I get queries from my friends who have recently bought a DSLR that whether they need an external flash for “better” photography specially for indoors. So I thought I would put my few comments of where external flashes can really make the difference and make your photos stand out from the “pop-up” flash photographs.

fill flash bright lighting situation

“Olga and Alex” captured by Tatiana Garanina (Click Image to See More From Tatiana Garanina)

The “higher” end cameras even do NOT have built-in flashes due to huge limitations of the in-built flash that can become bottleneck to their otherwise excellent image production quality. An external flash provide superior and “more” control over the lighting and exposure of the subject in low light (and even in bright light where you need to fill-flash) situations. Here’s why…

Flash Power and Distance

This is more obvious than the rest of the reasons but still this tops the list. With the power of the built-in flash (Guide number 13/43 at ISO 100) it becomes really difficult to illuminate “wide” angle shots and thus the edges of the photo remains too dark. With external flash you can get much higher range of illumination (Guide number 43/141 at ISO 100). Additionally an external flash has its own set of batteries thus enabling it to recycle faster so that the flash doesn’t drain the cameras batteries.

Note: It is important to understand that the effective distance of any flash depends on the Aperture and ISO. For example, at f/8 and ISO 100, the built-in flash will be effective only if the subject is within ~5 feet from the camera. Indirectly the range can be increased by decreasing F-stop and/or using a higher ISO setting. But both the methods come at a cost -

  1. less depth-of-field and
  2. increased digital noise

While a good external flash unit has about 15 times the power of a built-in unit, with approximately four times the effective distance (there’s some math involved here). Power also becomes critical for bounced flash and fill flash in sunny outdoor conditions.

external flash photography

“Music Video II” captured by Per Janus (Click Image to See More From Per Janus)

Ability to Bounce Your Flash

One of the most important things that dramatically affect the “quality” of photographs is the ability to “bounce” the light from the flash onto the subject via ceilings, walls or other objects. The built-in flash will produce a harsh-looking “snapshot” like photo as you cannot control the direction of the built-in flash. While a bounced light of adjustable external flash head can produce a pleasing photograph that doesn’t even look “flashed”. The method produces softer shadows, a brighter background, and more natural-looking results. Of course to be able to effectively bounce of the light, you would need quite powerful flash as with “bounced” light you are lighting up the whole room.

Reducing Red-eye

While we can always remove a red-eye caused by light reflecting off the retina in the back of the eye with dilated pupils (when in darker indoor areas) using post-processing tools like Photoshop on the photo, it is always advisable to take precautions while taking the photo itself. An external flash does a great job on this. The closer the flash is to the lens, the greater chance of the light coming out of the flash to reflect directly from the retina into the lens.

It also depends on the distance between the lens and the eyes. There’s some geometry involved here but the bottom-line is greater the distance between the flash and the lens, the further away the camera can be placed from the human subjects without causing red eyes. As you really cannot control the position of the in-built flash with respect to the lens, an external flash is an excellent solution.

Flash Accessories

These are “goodies” (modifiers, brackets and helper uses) that you can attach to your external flash for achieving better effects like “diffusers” that softens the harsh light of the flash. Also index cards can be attached to produce certain cat-eye effects. Another type of modifier is Better Beamer that produces narrow very powerful beams for wildlife shooting at long distances. Again you can get Flash brackets that moves the flash unit further from the lens thus lowering the risk of Red-Eye effect even less. They also help in portrait shots (vertical shots) in reducing shadows from the sides.

bounce flash photo

Photo captured by Dmitriy Bashaev (Click Image to See More From Dmitriy Bashaev)

You can deploy wireless flash setups in order to produce interesting studio like lighting sources from optimum directions. Some flashes include focus assist light that helps the camera’s autofocus system to work efficiently in low light situations. Also you can go for FP Flash (high speed sync) so that you can flash and still use of high shutter speeds. FP flash becomes necessary if you’re using fill flash outdoors but want to use a wide aperture to blur the background and hence need faster shutter speed than the sync speed. These small enhancements can really make a difference when it comes to professional shooting.

Which Flash to Buy? This depends on the compatibility factors and also the power requirements. If you have Canon EOS series DSLR, it is best to go for the 600EX-RT orĀ 580EX if you can afford it. If not, the next best choice would be 430EX (I have this model). If you have a Nikon DSLR, the best bet would be to get SB600 (reasonably priced). There are other alternatives like Sigma and Metz flash units available for both Canon and Nikon DSLRs.

About the Author
This article was written by Sudipta Shaw.

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