Light in Photography

"Without light there is no photography."
Light is an essential ingredient in any good photograph. How we use the light that is available that we, as photographers, are concerned about. The quality of the light and how it affects our photograph. Natural light ranges from cool to warm on the colour temperature scale and is measured in degrees Kelvin as is all types of light. Pre-dawn light has a blue tinge to it because of the reflection from the sky. At sunrise the colour is much warmer although not as warm as sunset aand doesn't last as long. As the sun rises in the sky it becomes cooler in colour until at it's zenith colours are completely neutral. As the sun then heads towards the horizon, it becomes warmer again until you get the reds and oranges of a beautiful sunset. The above would occur on a clear summers day. Next you have to add clouds which change the light as well. Light is normally categorised as Soft and Hard light. Soft light, in terms of outdoor photography, is that light produced on very heavy overcast day. The reason the light is so soft is because the clouds scatter the light decreasing the contrast andd leaving no or very little shadow. The dynamic range is said to be very small. Dynamic range is the difference between dmin and dmax, or the differnce between pure black to pure white. On an overcast day such as the one above range would be very small. Somewhere in the region of 4 to 5 fstops. Maybe not even that, especially on a rainy day. The next scenario would be a light overcast day where the clouds are very high. This type of sky actually works like a softbox on a studio flash. It scatters the light and softens the light but dthe dynamic rangewould be greater then above but not as great as a clear sky and bright sunshine at high noon. Hard light is when you have a large dynamic range with dark shadows with no or little detail and highlights also with no or little detail. This tends to happen on a bright sunny day when the sun is high in the sky. The dynamic range could be as much as 12 fstops. As you can see from above outdoor photography is a question of patience in waiting for the light you are looking for to light your image as you forsaw it. Personally I never use auto white balance. I set my digital cameras manually to approx 5750°K which is the colour balance of daylight film. For outdoor photography this renders colours more naturally. I also use this setting in the studio as studio flash is daylight balanced. How you use the available light is entirely an artistic decision. I hope this has given you some insight into the vagaries of ambient light and how it can be used to your advantage. Nikki H