Friday, April 17, 2009

Quality of Light - part 1.

As mentioned previously, Quantity, Quality, and Temperature are the three terms used to describe light in the studio. These correlate to the more common terms, Brightness (intensity), Contrast, and Color. The term Quality is in regard to the characteristics of light. In this context we are not referring to how good or bad the light may be, as that is entirely dependent upon the desired characteristics for producing a particular lighting effect.

When describing the quality of a light source, the term Contrast is synonymous with quality. What we are describing is the relative hardness (or softness) of a light source. Hard light is high contrast, which produces clearly defined shadows that are dark and have a hard edge. Soft light is low contrast, which produces faint shadows that gently feather at the edges. The softer the light source, the more difficult it will be to see shadows.


Here is an example of hard light. This photograph was taken with a snooted monolight. The snoot is a funnel like modifier that fits over the light to reduce the effective size of the light source. In this case it is 2-¼ inches (57 mm) in diameter. The light source is about 3 ft. (0.9 m) from the subject. Note how the shadow is well defined with edges that mimic the shape of the subject.



Next we have an example of soft light. This photograph was taken with the same monolight, but fitted with a 46” umbrella. The farthest bounce surface of the umbrella is about 4-½ ft. (1.4 m) from the subject. Note how the shadow is very soft with barely discernible edges.

In part two I will show the underlying principle behind this characteristic of light using diagrams that will hopefully shed light on the subject and explain why to a photographer, size does matter.

Stay tuned...

Continue on to "Quality of Light - part 2 (Hard Light)

5 comments:

  1. Thanks Gene for keeping it simple & short, But where is part 2??

    Thanks
    Gene G

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  2. I have just added links at the bottom of each page to make it easy to follow the series all the way through. Thanks for your comment.

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  3. I just found this site, however I wanted to add that you can have soft yet contrasty light. Contrast being the difference between what is lit and what isn't. Imagine a 6' softbox, split lighting pattern on a portrait. Lets say @ a distance of 10'. The light side meters @ f/8 and the shadow @ f/2.8. Now we move the light to 5' without changing the power. We will say it now meters @ f/11. We didn't change the shadow side, still f/2.8, what we did do was increase the contrast.

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  5. Actually, Anonymous, you are referring to the lighting ratio, which is a different beast from hard/soft light. Hard light produces sharp, distinct, high contrast shadows while soft light produces soft, low contrast shadows. Moving the light source closer will increase the intensity of light hitting the subject. It also increases the effective size, which makes the shadows softer. The key light becomes effectively a larger and softer light source. The fill side hasn't changed intensity, but the ratio between key and fill will have increased. However, note that the transition from the key area to fill area will now be more feathered.

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