Exposure 4541.762 Computational Photography

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Exposure(4541.762 Computational Photography)

• Jehee Lee
• Seoul National University

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Exposure Intensity x time

• Reciprocity
• The aperture controls the intensity of light that
  reaches the film
• The shutter controls the length of time the light
  strikes the film

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Exposure Meters

• Exposure meters averages tones in a scene
• Industry standard is color-neutral 18 gray

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Exposure Meters

• Hand-held vs built-in
• Reflected-light vs indicent-light

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Types of Exposure Meters
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Metering for Specific Tones

• Certain scenes can cause a meter to produce the
  wrong exposure

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Metering in Practice
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Metering in Practice
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Metering in Practice
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Exposing Hard-To-Meter Scenes

• Stage scene, sports arena, circus event 1/60
  sec, f/2.8
• Brightly lighted downtown street at night 1/60
  sec, f/4
• City skyline at night 1 sec, f/2.8
• Skyline just after sunset 1/60 sec, f/5.6
• Candlelit scene 1/8 sec, f/2.8
• Campfire scene, burning building at night 1/60
  sec, f/4
• Fireworks against dark sky 1 sec, f/16
• Fireworks on ground 1/60 sec, f/4
• Television or computer monitor image
• Focal plane shutter 1/8 sec, f/11
• Leaf shutter 1/30 sec, f/5.6

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Metering in Practice
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