Understanding Natural Light

Understanding Natural Light

colour temperature pic 1

Light is absolutely fundamental to photography – and in fact the word photography derives from the Greek words “phos” (light) and “graphé (drawing) – translating as “drawing with light”.

The type of light in any situation will also fundamentally affect the way our photograph appears. And yet, it’s very easy to take the light for granted, and not to notice the quality or type of light that is prevailing.

This is not just because we photographers are lazy and unaware! A large part of the reason is that our human eyes and brains are much more sophisticated than a camera, and compensate for differences in the quality of light. For instance, in a scene with bright light and dark shadows, we see everything fairly evenly illuminated – but the camera can’t cope so well with the brightness range, and so in the photograph there will be a lot of contrast.

Natural light varies in several different ways. First is the quality of the light in terms of being hard or soft. A hard light is the kind you will get from the sun in a clear sky. At the other extreme, a completely overcast sky will result in a soft, diffused light. Between these two, a light layer of cloud can give a bright but still diffused light.

Hard light will illuminate some areas brightly while casting others into dark shadow; soft light will provide a much more even illumination throughout the scene.

Secondly, the direction the light is coming from will dramatically affect the resulting photograph. On an overcast day, when the light is diffused, the direction of the light won’t be much of a factor. But on a clear day, the light of the sun can come from various different directions – high overhead, or low in the sky, from in front of you, behind you, or from your side.

When the sun is right overhead, it will seldom be a good light for photography, as it creates contrast without revealing any shape or texture. For landscape photography, a low light coming from the side is often considered to be the best, as it skims across the landscape, emphasising every contour. If you’re photographing a smaller subject, such as a flower, or making a portrait of a person, side light can also be lovely, but you may need to balance it slightly by using a reflector to push some light back into the shadowed side of your subject.

When the sun is in front of you it can create lovely backlighting on translucent subjects, or make dramatic silhouettes out of solid ones. Light coming from behind you will show colour and detail in a subject, but not show its texture as much as side light will.

One of the qualities of light which is harder for us to notice is the colour temperature. Natural daylight has a range of colour temperatures, which we are often not aware of because our eyes compensate to make them all appear much the same – but the camera’s sensor will record the differences in the colour temperature of light.

At the beginning of a clear day, when the sun is low in the sky, the light will have a warm, reddish colour cast. As the sun climbs, this gets cooler, and when the sun is overhead, the colour cast will be quite cool and blue. Then as the sun goes back down towards the horizon, the colour cast warms up again.

On an overcast day, the light will have a cool, blue colour cast; and if you photograph a subject which is in the shade on a clear sunny day, it will also have a blue colour cast.

We can compensate for these colour casts by using the white balance menu in our camera – for more detail about this, see my blog on November 7th 2012.

We can’t control the type of natural daylight that we find in any situation, but if we become more aware of its qualities, then we can understand how to make the best use of it in our photography.