A question that most amateur DSLR users seem to ask is what is the correct use of the pop-up flash on their camera? The pop-up flash, as you know, is the one that springs into position when you push that tiny lightning marker at the top of your camera. This tiny flash fires an intense beam of light that illuminates subjects that are within a distance of 10-15’. However a major problem with the pop-up flash is that they are difficult to control and to focus with pin point accuracy. Thus most professionals and senior photographers prefer not to use this flash. Read more about how to choose external flash for professional photographers.
Having said that, this flash is particularly useful when you are shooting something in extremely dark conditions and need a way to be able to make a proper exposure. The pop-up flash is your one good chance of making an exposure when you don’t have enough natural light and somehow forgot the camera bag in the car. However, if you want to do creative photography, you will require an off-camera flash.
Use it as a fill-flash
The pop-up flash works great as a fill-flash. A fill-flash, as the name suggests,is used for filling in shadows when natural light cannot. Let’s say you are shooting in bright sunlit conditions. The sun is at your 12 o’clock. You know there’s no way you can create a backlit condition as no matter which way your subject turns the sun is still going to bear straight down on her. What follows next is strong shadows under the nose, chin and deep black bags under the eyes. To avoid such a situation you could try using a diffuser and create some shadow. May be even ask the subject to stand under a tree or wall. What if there’s nothing to work with at all? The easiest solution is to use the pop-flash on your camera in fill-flash mode. When you use the flash in fill-flash mode it subtly takes care of all the shadows and balances the exposure.
Use the flash to illuminate subjects that are closer to you
One thing that you should never do is use the flash to illuminate something too far away from the camera. This piece of advice comes directly from the inverse square law. The inverse square law is applicable for explaining a lot of things in physics. It is extremely important in explaining how light too behaves and thus is a very important in photography.
Place a series of white balls at equal distances, say 2’, 4’, 6’, 8’ and 10’. Raise the flash and make an exposure. You will notice that the ball closest to you is overexposed with highlights. The ball at 4’ would be properly exposed. The ball at 6’ would be grossly underexposed. The balls beyond that would be underexposed as well but the difference when compared with the ball at 6’ would be marginal. This phenomenon of drop in intensity of light is known as light fall-off. Light tends to lose its intensity quite dramatically over the initial distances. After that the loss in intensity is marginal.
Thus, when using the pop-up flash, ensure that you only use it for subjects that are closer to you and not hundreds of meters away. I have seen people firing their pop-up flash for photographing a twilight seascape shot. I would love to know the reason for that.
Using the pop flash in rear-curtain sync
I have already discussed the techniques of rear-curtain sync elsewhere on this website, thus will not go through the entire process once more. Just that a pop-up flash works just as fine for freezing movements when you are shooting in low light conditions. The rear curtain techniques helps you achieve that easily.
If you are photographing still life that is backlit it poses a challenge. Let’s say that the bride and the groom wants you to take a picture of asmall group against the twinkling lights at the venue. The problem is the lights are behind them. To crack the problem you need to employ a slow shutter speed. The slower shutter speed will allow you to soak in the ambient light, properly exposing for the lights and making them dazzle in the final shot. The flash will need to be fired at the end of the exposure (rear-curtain sync) which will ensure that the subjects are properly exposed and suppress any movements during the exposure. For a larger group, though, the pop-up flash would be unsuitable. You will need an external flash or better still a strobe.
Read more about reasons to invest in external light.