The quality of light is often described in terms of hard or soft light. These terms may seem a bit nebulous. If you tell a non-photographer that you took a picture in soft light, she will probably have no idea what you are talking about. Actually, there is a somewhat objective way to view hard and soft light. Hard and soft light can be characterized in terms of contrast, shadow detail, and dynamic range. In addition, although less objective, hard and soft light can be characterized in terms of the emotional response that each tends to create in the viewer.
Hard light is a very direct, harsh, often unflattering light.
Figure 7 is an example of hard light. This image was shot in the desert under the mid-day sun. The result is a rather unflattering image. The sunlit earth is very bright and the shadows hold little or no visible detail. This image may be of interest to someone who is interested in old cars or car remains, but it would not hold the interest of most other people.
Hard light has a very high contrast. This can be seen very well in Figure 7. The dirt in the sunlight is very bright almost to the point of being uncomfortable. The dirt that is in shadow is very dark. Furthermore, the dividing line between the sunlit and shadow areas is very sharp, almost knife like. At no point in this image is there a smooth transition from light to shadow. The changes are all abrupt.
Hard light tends to lack shadow detail. As can be seen in Figure 7, it is very hard to see any detail in the shadow areas under this hard light. One could bring out the shadow detail with some extra exposure, but that would make the sunlit dirt even brighter. This lack of shadow detail is related to the large dynamic range of hard light. Dynamic range is a measure of the span of tonal values over which a device (in this case a camera) can hold detail. In other words, it is the tonal distance from the darkest point at which the device holds detail to the lightest point. Dynamic range is measured in stops of light. When light is increased by one stop, the amount of light is doubled. (going in the other direction, it is cut in half). Color print film and the better digital cameras have a dynamic range of about five or so stops. That means that the brightest areas in which they can hold detail are about 32 times brighter than the darkest areas that hold detail (each stop is a doubling of light, so five stops = 2 X 2 X 2 X 2 X 2 = 32). Color slide film only has about three stops of dynamic range. Unfortunately, an environment illuminated by hard light can have ten or more stops of dynamic range. In other words, your camera can not capture all of the detail (unless you are shooting with black and white film some of which can have a dynamic range of around ten stops). In hard light conditions, either the highlights or shadows will likely lose detail when photographed in color. Generally, experienced photographers prefer to lose detail in the shadows rather than the highlights -- thus, the lack of detail in the shadows in hard light conditions.
Hard light generally creates feelings of harshness or starkness. Often, this is an uncomfortable feeling. This can work to the detriment of the photographer. For instance, a beautiful flower shot in hard light conditions will not look very attractive. Part of this is due to the harsh contrast and dark shadows. Another factor is the fact that hard light generally tends to desaturate colors. So, in addition, the flower will have washed out colors.
However, this does not mean that hard light should never be used. Hard light has its place. Hard light can be used to emphasize harshness or starkness. For instance, a photographer may choose to shoot a desert scene in hard light in order to emphasize the harsh nature of the environment. Figure 8 is a case where the photographer deliberately chose hard light to accentuate this desert grave and its harsh environment.
Hard light is created when a scene is illuminated by a small light source. Direct mid-day sun is a typical example. While the sun may be very large, it is also very far away and appears to be small to a person on earth. Thus, direct sunlight that is not filtered or reflected in any way tends to be hard. As a result, photographs taken in clear sky conditions during the day will exhibit the typical traits of hard light.
Quality of Light: Hard
Figure 7: Hard Light
Figure 7 is an example of hard light. This image was shot in the desert under the mid-day sun. The result is a rather unflattering image. The sunlit earth is very bright and the shadows hold little or no visible detail. This image may be of interest to someone who is interested in old cars or car remains, but it would not hold the interest of most other people.
Hard light has a very high contrast. This can be seen very well in Figure 7. The dirt in the sunlight is very bright almost to the point of being uncomfortable. The dirt that is in shadow is very dark. Furthermore, the dividing line between the sunlit and shadow areas is very sharp, almost knife like. At no point in this image is there a smooth transition from light to shadow. The changes are all abrupt.
Hard light tends to lack shadow detail. As can be seen in Figure 7, it is very hard to see any detail in the shadow areas under this hard light. One could bring out the shadow detail with some extra exposure, but that would make the sunlit dirt even brighter. This lack of shadow detail is related to the large dynamic range of hard light. Dynamic range is a measure of the span of tonal values over which a device (in this case a camera) can hold detail. In other words, it is the tonal distance from the darkest point at which the device holds detail to the lightest point. Dynamic range is measured in stops of light. When light is increased by one stop, the amount of light is doubled. (going in the other direction, it is cut in half). Color print film and the better digital cameras have a dynamic range of about five or so stops. That means that the brightest areas in which they can hold detail are about 32 times brighter than the darkest areas that hold detail (each stop is a doubling of light, so five stops = 2 X 2 X 2 X 2 X 2 = 32). Color slide film only has about three stops of dynamic range. Unfortunately, an environment illuminated by hard light can have ten or more stops of dynamic range. In other words, your camera can not capture all of the detail (unless you are shooting with black and white film some of which can have a dynamic range of around ten stops). In hard light conditions, either the highlights or shadows will likely lose detail when photographed in color. Generally, experienced photographers prefer to lose detail in the shadows rather than the highlights -- thus, the lack of detail in the shadows in hard light conditions.
Hard light generally creates feelings of harshness or starkness. Often, this is an uncomfortable feeling. This can work to the detriment of the photographer. For instance, a beautiful flower shot in hard light conditions will not look very attractive. Part of this is due to the harsh contrast and dark shadows. Another factor is the fact that hard light generally tends to desaturate colors. So, in addition, the flower will have washed out colors.
Figure 8: Hard Light
Hard light is created when a scene is illuminated by a small light source. Direct mid-day sun is a typical example. While the sun may be very large, it is also very far away and appears to be small to a person on earth. Thus, direct sunlight that is not filtered or reflected in any way tends to be hard. As a result, photographs taken in clear sky conditions during the day will exhibit the typical traits of hard light.
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