Measure Relative Intensity (Contrast)in a Digital Camera

The term quality has, referring to light, a different meaning than usual; it doesn't distinguish between "good" and "bad light, but between hard or contrasted and soft o r diffused. A punctual light source, such as direct sunlight, a flash or an incandescent lamp, produce a hard and directional light . The more concentrated the source or the greater distance it is, the more directional the light. Therefore, in a space illuminated with hard light, the border of the shades is cut out, and the

differences in brightness are accentuated by the drastic change of light to shadow. An extensive and uniform source of light, like the sky with no sun, or the light reflected by a large surface, is a soft light, only slightly directional. In a space illuminated with soft light, the shadows diminish, it's border fades, and the change from light to shadow is gradual.