Selasa, 17 September 2013

tata cahaya

Lighting:
Hard and Soft Light




The art of cinematography is the art of lighting
and making that light tell the story.
-Stephen H. Burum, ASC
(Apocalypse Now, Carlito's Way, Mission Impossible,
Body Double, Life or Something Like It,etc.).
Lighting can emphasize important details or hide them. It can flatter a subject by bringing out positive attributes, and it can de-emphasize or hide less attractive attributes. Lighting can even impart a sinister and hostile look. It all depends on how you choose to use the concepts we'll be covering in the next few modules.
Television is based on the medium of light; in fact, without light there could be no video. Just as sound must be skillfully controlled in audio production, light must be expertly controlled in television.
As video—especially HDTV—has begun to emulate the more artistic dimensions of film, there has been a greater emphasis on creative lighting. But, before you can successfully control light, you need to understand and control its three basic characteristics:
• coherence (quality)
• color temperature
• intensity
In this module we'll cover the first of these —


Light Coherence
Coherence, often called quality, is the hardness or softness of light. Light quality is probably the least understood and the most neglected of the three variables.



In the photos above the objects are exactly the same. Two of the variables of light are also exactly the same: intensity and color temperature. The only difference is the third variable: the coherence of the light. The first photo was shot with soft light, the second with a hard light source. (In Module 35, "Altering Appearances," we'll look at additional factors that can affect the appearance of subject matter.)

Hard Light
Light that is transmitted directly from a small point source results in relatively coherent (parallel) rays. This gives the light a hard, crisp, sharply defined appearance. The light from a clear, unfrosted light bulb, a focused spotlight, or the noonday sun in a clear sky, all represent hard light sources.
Hard light casts a sharp, clearly defined shadow. When hard light is used to illuminate a face, imperfections in the skin stand out. The result is less than flattering. But in other applications, such as bringing out the texture in leather, or the engraving on a piece of jewelry, this can be an advantage.
Note in the photo on the left how the writing stands out. Also note the clearly defined shadow of the flower at the bottom of the photo. Compare this photo with the one in the section below (with soft light) where the letters are hard to read and the shadow of the flower has all but disappeared.
Several types of lighting instruments are used in TV to create hard light, including the beam-spot projector and the ellipsoidal spotlight.

Soft Light
Soft (diffused) light has the opposite effect. As shown in the photo on the left below, soft light tends to hide surface irregularities and detail.


Spun-glass diffusers (above) are used over the front of lights to soften and diffuse their beams. Note resulting photo on the left. At the same time, diffusers also reduce the intensity of light.
Soft light sources are used in production to create a broad, even area of light. In the field, videographers often rely on umbrella reflectors (on the right, below) to create a soft lighting effect. As you can see, this is simply a light bounced off the inside of a silver or white, umbrella-like reflector. The illustration below on the left shows a much heavier soft light that is commonly hung from the grid in studios.



Because soft light tends to hide lines, wrinkles and blemishes, it's desirable in doing glamour work. The photo of the model on the left was shot with soft light.
A soft light source placed close to the camera minimizes surface detail. The effect is commonly referred to as flat lighting.
Although it has certain applications, especially in extreme close-ups of objects where shadows would obscure important details, flat lighting leaves subject matter somewhat "dimensionless." When used over a large area, it can impart an arid and sterile-looking appearance.

Ultra-Soft Lighting
There are a few occasions when ultra-soft lighting is necessary to keep video equipment from exceeding its brightness or contrast range limitations and compressing (losing) important detail.


Compare the picture on the left with the one below. Note that when standard lighting is used (on the left) the reflections from the shinny objects drive down the video levels in the darker areas. (Recall the illustration of video spikes in Module 16.) As a result, important detail is lost.

The same problems are encountered when you photograph shiny metallic objects such as jewelry and silverware.
These problems can be fixed (as seen on the left) by using an extremely soft lighting setup—in this case the lighting tent shown below.
To create this ultra soft lighting the subject matter was surrounded by a white sheet, leaving only a small opening for the camera lens. Three lights placed at different angles lit the sides of the sheet.

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In this module we've illustrated the two extremes: hard light and soft light.


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