The Right Light
Getting the right light is the all important bit of capturing an image. Light is everything yet not all light is the same. There are many different light sources both natural and artificial, all of which can have dramatically different effects. For this discussion I will simply concentrate on natural daylight.
For our purpose light has two main characteristics. Its luminous intensity (candela) and its colour temperature. Yes, visible light is electromagnetic radiation that is considered a wave and thus has a frequency, propagation direction, polarization and speed. But lets just concentrate on photography here! Assuming the weather is good both parameters actually depend on the angle of the sun. The lower the elevation in the sky the lower the intensity and colour temperature. Lower intensity lets us use longer speeds and helps with softer tones. We also get wonderful shadows to play with. Now for the important bit – colour!
Colour temperature is measured in degrees Kelvin and ranges from 5500K (cool blue) during the day to about 2500K (warm yellow) as the sun is setting or rising. This change in the colour of the available light can have a profound effect on a picture.
The best way I can represent the effect of different colour temperatures on a scene is by the two pictures above. They are of the same place on the same day. They are also taken on the same film (Velvia 50) with similar wide angle lenses. All that is different is the time. The image on the left was taken in the middle of the day. The one on the right was taken as the sun was setting, just before it disappeared below the horizon.
It doesn’t stop here though. There is also another very important colour change that happens as the sun sets or rises. This depends upon where you are standing. For those too busy looking at the sun, turn around and look the other way! You’ll notice a purple/ pink haze developing instead of the orange/yellow 180 degrees behind you.
Most people seem to miss this so next time the sun is setting on a clear warm day, look around! And not just with the camera. To quote the late Galen Rowell “You only get one sunrise and one sunset each day and only so many days on this earth to enjoy them”. I simply could not have put it better. So no matter what hour of the day, how early or late, get out there and enjoy them. Leave the camera at home if you have to! But remember, if you are looking for that great picture the right light doesn’t wait around.