文档介绍：changing light _ 131
CHANGING
LIGHT
T he beauty and challenge of natural light is that it is
constantly changing. A picture taken from the same spot with
the same settings will not only look different whether taken
in the morning or afternoon, it may also be transformed from
one moment to the next. These subtle changes in lighting can
make a big difference to your pictures. For this reason, outdoor
photographers can e obsessed with weather reports,
and the time and position of the rising and setting sun.
It is not just the direction of the sun that varies throughout
the day in relation to the subject. Its height changes the length
of shadows and also changes the intensity and diffusion of
light. Low in the sky, the sun’s rays are scattered by particles
in the atmosphere, creating softer illumination. This effect
varies significantly depending not only on the time of year but
also on the latitude. The closer you are to the equator, the
fewer changes there are in the lighting between the seasons,
and the more steeply the sun rises. The glorious low, raking
light at dawn may last only a matter of minutes.
In temperate zones, lighting quality not only changes
more significantly throughout the day, but is also more
dependent upon the meteorological conditions. A single cloud
can have a major impact on the lighting conditions. It may
improve things—reducing contrast and softening the colors;
but with some subjects it may be better to wait for the cloud to
move. The moment you choose to take the photograph is
crucial; great results often require a great deal of patience.
2TEMPERATURE CONTROL
The warm glow that remains after sunset is caused by the sun’s rays
having to pass through more atmospheric particles at a low angle.
Some wavelengths rate better than others. The color effect can
be controlled using white balance (see pages 58–59).
132 _ lighting
I n addition to affecting the direction, diffusion, and