Fill Flash Demystified

Article by Jitesh (4,000 pts ) , published Apr 27, 2009

Fill flash is one of the easiest to use, yet often ignored, photography techniques. This article explains the basic concept of fill flash and provides tips on how and when to use fill flash to help you take better pictures.

Introduction

How many times have you attempted to take a beautiful snapshot of your spouse or child, got the background perfectly exposed but ended up with a dark face or, even worse, a silhouette? How many times, on a perfectly sunny day, do you end up with dark or underexposed subjects? If this sounds familiar, continue reading to discover why this happens and how adapting a simple technique, called ‘fill flash’, will make this an issue of the past.

The Problem with Shooting in Auto Mode

Let me first explain why this phenomenon occurs, as understanding the cause of a problem is vital to understand its solution. Usually while taking a photo, the camera ‘meters’ or decides how much light is available in a particular situation, and sets the aperture and shutter speed accordingly. Usually, today’s digital cameras do a pretty good job and accurately decide the right settings in most commonly occurring situations, but very bright or very dim light can complicate matters. If a scene has very bright background, the camera is ‘fooled’ into exposing for the brightness, and ignores the subject placed in the foreground. The bright background caused the camera to fix a very low shutter speed or narrow aperture (or both), resulting in the bright background getting properly exposed, but the foreground getting underexposed. This is the main reason for dark faces in otherwise perfect photos. If we set the camera to meter for the foreground subject, a longer shutter speed or wider aperture is chosen, which results in blown out and over-exposed background.

So, what's the method to get both the foreground subject and the background perfectly exposed? The answer is very simple: use the flash!

Understanding Fill Flash

For an amateur or beginner photographer, it may seem very confusing to be using the flash in bright daylight. Many point-and-shoot digital cameras might even refuse to do that when used in the ‘Auto’ mode. But the logic here is quite simple - the dark faces are primarily due to insufficient exposure. A flash throws just about enough light on the foreground subject, making it temporarily comparably bright as the background, and thus getting it properly exposed. So, the flash basically ‘fills’ light in the relatively darker foreground, and hence this technique is known as ‘Fill Flash’.

Many digital cameras allow a person to control the intensity of the flash, a setting known as ‘Flash Exposure Compensation’ (FEC). Changing this setting increases or decreases the intensity of the flash. If your camera offers this setting, it's highly recommended to use it to give a more natural feel to the flash filled area. So, what are the parameters to be kept in mind while altering FEC? Firstly, the distance of the subject from the camera. Next, the lighting conditions, viz., angle and intensity of light falling on or behind the subject. One has to take care that if he is quite close to the subject, the flash intensity should be set a stop or so less, so that the subject is not overexposed and vice versa, if the subject is relatively afar. An average digital camera has a flash range of only up to 10 feet. So, if the subject is beyond the range of your flash unit, this technique may not work.

Another consideration, as mentioned earlier, is that quite a few digital cameras do not allow flash to fire if set in ‘Auto’ mode in bright conditions. In such cases, it may be necessary to set it to ‘Force Flash’ mode. This mode is usually represented by an icon similar to a bolt of lightning.

Please continue on to page two of this photography article to learn tips on when and how to use fill flash.

Subscribe to Digital Photography
RSS
Get free weekly updates, directly to your inbox.
Browse Digital Photography