Light is the most important element in photography. In fact the word photography comes from Greek meaning ‘to draw with light’. The way light interacts with objects is the reason for color, shape and texture. Being able to control and manipulate light so that you can creatively affect these variables in your photographs is like unlocking a new world of possibilities.
Lighting is one of the only aspects of photography where I feel that a basic understanding of the theory behind it can actually give you the ability to be more creative rather than restricting you. I am not a physicist and so I don’t necessarily need to know the reasons why, I just need to understand how the principles of light can be harnessed in my images. As far as ‘rules’ or theory go in lighting there are two main principles which, if understood, will give you a great blank canvas to start being creative with lighting.
The two principles which will be of most use for off-camera lighting will be the Inverse Square Law and the understanding of how relative size of your light source affects the light quality. How will these affect my images you may ask? The Inverse Square law basically states that as you double the distance between the subject and light source, the effective power of your flash will reduce by a quarter. Therefore in practical terms you need to understand that light falls off much faster the closer your subject is to the light source.
The distance from the light source to the subject also affects its relative size. The larger the relative size of the light source to your subject the softer the shadows the light source will create. This is the property of light which causes the sun to cast harsh shadows at midday. Despite the fact the sun is a huge light source, its distance from earth means that its relative size is fairly small, this combined with the steep angle of the sun at midday is the reason why you will get the harsh, unflattering shadows.
Understanding and using the concepts of light is something that has been developed in the world of art for many centuries. Whole art movements have been founded on the use of light and shadow to create more realistic drawings and paintings. By studying how light is used in other artistic mediums can help us to see ways of utilizing light in our own imagery. The most important lesson that I think you can take from classical artists especially is their use of shadows to create depth in an image. Upon purchasing a flash gun, the first thing many photographers do is set it up to create even, shadowless lighting. This is all well and good if your aim is to produce flat lifeless images.
For many shadows are this dark, mystical creature that they are scared to embrace in their photographs. However, learning to produce shadows in the correct places in an image can help to convey a different mood, emphasize or hide certain elements in an image and much more. Shadows are a photographer's tool to convey 3D qualities such as depth, volume and texture in the two dimensional medium of photography.
The creative possibilities of using off-camera flash are almost boundless and to try to explain them all in this single blog post would be pretty much impossible. Therefore I am going to take a quick look at a couple of my favorite techniques which you can easily incorporate into you documentary work.
Lighting plays an important role in building the mood and atmosphere and when I am trying to convey a mood that isn’t a happy one or is maybe dark or mysterious I chose to take a more low key approach to lighting. Low key lighting is extremely powerful in this sort of scenario as you are able to remove virtually all distractions from a scene so the viewer can concentrate on your main subject.
When shooting low key images the hardest part is stopping the light spilling all over the scene and lighting up the background. To help keep the background dark, I used a really high shutter speed of over 1/2000s to completely kill the ambient light in the scene. This effectively gave me a blank canvas to work with in terms of lighting my two subjects. Feathering light is a nice way of producing soft light that has a nice gentle appearance.
Basically, to feather light you have to point the centre of your light away from your subject so that only the edges of the light are actually reaching your subject. The edges of the light are generally much softer compared with the centre which, when using speed lights in softboxes, can sometimes form a hotspot of stronger uneven light. You have to remember to feather away from your background or to move your subjects further away from the background to help prevent too much background light spillage.
A second technique I like to use in my documentary work is replicating natural light by using a gelled flash. This is particularly useful if the natural weather conditions are not playing ball or if you just want to add some drama to a fairly plain scene. When I want to mimic the light that is already in a scene, my starting point is to place the light exactly where the natural light is coming from. Working in the field in small houses and dwellings means that generally I will be placing the softbox in the window or door way. In my style of photography I am not looking to radically reinvent the lighting, especially if the natural light is looking good already.
You can also add color to your flash, replicating early morning/late afternoon light, by placing a weak 1/4 CTO gel onto the flash head just to give it a slight boost in warmth. The gel on the flash can help aid the impression that the shot was made towards the beginning and end of the day rather than right in the middle of it.
The final technique I want to look at in this blog post is using your flash gun to replicate artificial or small natural light sources which are included in the scene such as candles and light bulbs. The key thing to remember when mimicking light sources already in your images is the how the shadows in your images fall. If you are not careful with the position of your external lighting source shadows it can make the image look really obviously fake. Not the ideal situation when you are trying to achieve natural results.
For the lighting in most shots that mimic small natural sources such as candles and fires I use at least one full CTO gel which allows me to replicate the lantern/fire/candle light as both the source included in the and flashgun are a similar color temperature. By placing the gelled flash in the same direction as the light sources in the image you can almost completely hide the fact that the shot is lit externally.