LIGHT, AS WE ALL KNOW, is everything in photography. No wonder then that it is so hard to work with a digital camera’s flash. Sure, everyone can get a half decent shot about half of the time by relying on the built-in meter and auto-exposure system, but the results will be disappointing as often as not.

As with so many things in life, there is a right way and a wrong way to work with you camera's flash.

No matter if you are using the built-in popup flash or a dedicated hot shoe unit, there is so much more to flash photography than simply blasting the subject with light.
One of our biggest challenges is to learn to understand how the light that shines on the subject will translate visually into the final image.

'Reading' how the contrasts of shadows and highlights will affect the photograph is difficult enough when we are presented with available light, but when we have to 'paint' with fleeting flash bursts, with a luminous lifespan way too short for the eyes and brain to interpret into visual information, it becomes very hard indeed.

For the first few years of my photographic life, flash was my pet-hate. I despised it and loathed it. I started my life as a professional photographer without a flashgun in my bag, and the pop-up flash on my Pentax MZ5-N taped shut so that it wouldn’t ruin my shots. I was a confirmed flash-o-phobe.

Until I learned how to use it…

The wrong way:

A flashgun is a powerful beast and a delicate creature, all at the same time. And once you’ve tamed it, it can be your loyal companion and partner in beautiful pictures for as long as you both shall live, but in the hands of the unwary amateur it can be a bull in a china shop.

Anyone who has ever spent any time with a point-and-shoot camera has experience with the 'wrong' way of flash photography. With these cameras, when the camera's light meter detects light levels that are too low for an accurate exposure, it automatically power's up the flash and, when the shutter is released, floods the subject with direct light.

While this method has utility in certain circumstances, it can lead to some common problems.

The first and most obvious is that it can often lead to severe red-eye. This is caused by the strongly directional light shining from an angle close to the lens passing through the subject's enlarged pupil and bouncing off his retina. Of course, there are various ways of dealing with red-eye. The first is by firing a pre-flash, which forces the pupil to contract and thereby avoiding the problem. The second is by removing the red tint afterwards, by using a software program such as Adobe Photoshop.

These two methods, though both work to a certain extent, each have their own shortcomings. The pre-flash method forces the camera to wait for a period of time between the moment when the shutter release button is pressed and the moment when the picture is actually taken. This time lag removes the spontaneity from pictures and, where the timing is critical, can ruin the shot completely.

The software method's main problem is that it is time consuming, and that some serious cases of red-eye may be completely beyond repair.

Another problem that rears its head with the point-and-shoot variety of flash, is that it invariably causes a silhouette shadow behind the subject. This is particularly noticeable where the main subject is close to a plain, light colored background, such as a white wall. The light burst will leave a trace shadow right behind the subject and can also leave unflattering shadows around the nose and chin.

The third problem is that of falloff. The further the subject is away from the flash, the less light it receives from the burst, meaning that foreground details can often be hugely overexposed while background details are far too dark to even show up in the image. This falloff is quite rapid, and, for flashguns which do not focus the light beam, there is a three quarter loss of light intensity for each doubling in distance.

This problem is best demonstrated by a picture taken at night, where the ground close to the subject is visible. The ground closest to the camera is intensely lit, even to the point of being blown out, but it gradually fades into blackness as the distance increases. It is also particularly acute where subjects are varying distances from the camera.

Finally there is the problem of monotony. If all pictures taken after dark is taken with the light shining from a position very close to the camera's view-point, it will make for very dull pictures indeed.

Fill-in flash photography

The first flash technique every photographer should get to know is fill-in.

While most photographers are used to firing a flashgun in the dark, using the gun in full daylight can also improve pictures.

Fill-in is a technique which requires a small burst of flash, even in bright, sunny circumstances. In fact, it is most often used where there is a big contrast between very bright highlights and deep shadows.

The small burst lowers the contrast by mainly affecting the dark areas. It is especially useful when taking pictures of people wearing hats, where the eyes would otherwise be obscured by dark shadows.

The technique looks most natural if the flash burst is about a stop darker than the ambient light, but most cameras will measure for this automatically. More often than not, all you need to do is manually turn on the flash in bright conditions, and viola, fill-in flash.

Where you want to manually adjust the brightness of the fill-in burst, take a light reading of the sunlit areas, then set the flash to one or two stops less than would be required to match this. This second, manual method allows for greater control.

Fill-in is most often used in portraiture, but it is by no means limited in its scope. It can just as easily be used in close-up photography and even architectural photography.

Slow sync flash and ambient light

The problem with many cameras’ exposure systems is that, if they are presented with low light situations, they tend to overpower the ambient light with a very bright flash. An alternative method which looks much more natural is to adjust the flash to about one and a half stops ‘underexposure’, and then to lengthen the shutter speed or open the aperture by the same amount.
This will cause the camera to record the scene in a much more natural way, a greater degree of natural light while overcoming the problem of underexposure.

Using flash falloff to your advantage

A technique which is very common among wedding photographers is to separate the foreground subject (in their case, more often than not, the bride) from the background by adding a small amount of flash.

Because falloff will cause the intensity of the light to diminish as the distance from the camera increases, a small amount of flash will highlight those objects closer to the camera while leaving those further away untouched.

This leaves the foreground subject much lighter and more radiant than the dark and underexposed background, allowing you to seperate the foreground and background through the use of contrasting lighting conditions. This technique is therefore also very useful when you are faced with a busy, distracting background. For the best results, take a light reading of the background, then set to one or two stops overexposure and allow the flash to fire on automatic, or set it manually for better control.

Bounce the flash off the ceiling

Bouncing a flash does not mean you drop it from a high building, and you do not need to buy a rubber flashgun. You will, however need a gun with a rotatable head, which means that this technique is usually off limits to those using a built in pop-up flash.

By rotating the flash head and pointing it at a reflective, neutral colored area, such as a white ceiling, you can bounce the light off a larger area, thereby softening the light which reaches the subject.

It also allows the photographer with a much more versatile method of controlling the lighting, as the flash burst will now effectively be coming from a different angle.

Bouncing the flash is a very powerful technique, but to use it to greatest effect, there are also some things to remember.

The first is that if the flash is bounced of a colored surface, this may cause the picture to have an overall colorcast. Neutral or white colored walls and ceilings work best, but if there isn’t one nearby, you can improvise by using a large white card or a custom made reflector which can be folded and kept in your camera bag. You can, of course use the color cast caused by bouncing the flash of a colored surface to great effect, but don't be caught unaware, or you might need to spend many hours in photoshop fixing the problem.

The second is that the angle at which the light hits the reflective surface is equal to the angle at which it bounces of that surface, so you may have to carefully align the flash head to light the subject exactly the way you want.

Slow sync flash and the rear curtain

This technique is most often used with action photography. It requires a burst of flash just before the end of a long exposure. In normal flash photography, the shutter opens for only a very brief period of time, allowing only the light from the flash to be recorded. By lengthening the exposure, the CCD or film will first record the ambient light and then, provided the camera and flash combination supports this function, just before the rear curtain of the shutter closes, the flash is fired.

When this technique is used with a moving subject, the period before the flashgun fires will be recorded as a blurred streak, and at the very end of the exposure a sharp image of the moving object will be captured by the very brief flash.

Imagine a ball flying through the air. As the shutter opens, the ball moves a distance and this is recorded as a blur, but when the flash fires, a brighter version of the ball is recorded during the brief instant of light.

Needless to say, slow syncing flash with the rear curtain is one of the best ways to suggest movement in a still photograph.

Multiple Flashes

Like the previous example, here the shutter remains open for a period of time, but here, the flashgun is fired a number of times during the exposure.

With our example of the ball flying through the air, the ball will be stopped every time that the flash is fired.

But this technique is a lot more versatile. You could for instance remove the flashgun from the camera (provided it is of the hot shoe variety) and then light different parts of the scene with flashes from different directions. You could even move the same object around, and fire the flash a number of times, thereby effectively creating a multiple exposed image. Just imagine, you could photograph yourself playing chess against yourself without the use of Photoshop!