Exposure 1

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Exposure 1

• Exposure is the control of light reaching the
  film or digital imaging sensor. In most modern
  cameras the computer electronics does a pretty
  good job of evaluating the scene and setting the
  exposure controls to get a usable image.

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Exposure ?

• However, sometimes the camera scene evaluation
  system can be tricked or it might otherwise guess
  incorrectly in taking the picture the way you
  want.

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Feed Me!

• Photography, film and digital, are light hungry
  beasts. Generally the more overall light in the
  scene the better the camera does at evaluating
  and recording the scene.

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Too Much/Too Little

• Too much light, just as much as too little light
  will result in an unattractive photograph.

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Just Right!

• Getting the ideal exposure is not only a tricky
  technical problem, it is also a matter or
  personal taste and artistic intent.

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Goal

• The goal of a modern camera's exposure system is
  to automatically set the camera for the just
  right amount of light or to help the
  photographer set the camera to get what they want.

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Goal

• Thus it is useful to have some understanding of
  how the camera's computer electronics sets the
  exposure so that you can choose the best
  automated settings or even judge when and how to
  override the system.

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Exposure Control

• There are several ways to control the light
  reaching the film or imaging chip.

• Amount of light getting into the camera
  (Aperture)
• Period of time that the light gets in (Shutter
  speed)
• Sensitivity to the light (ISO)
• Change the lighting in the scene (Flash, etc.)

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18 Middle Gray

• General photographic theory states that the
  typical ideal photograph should have an equal
  balance of Black and White.

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18 Middle Gray

• General photographic theory states that the
  typical ideal photograph should have an equal
  balance of Black and White.

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Balancing Act

• The Camera's exposure system tries to find an
  even balance between Black and White.

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Balancing Act

• The Camera's exposure system tries to find an
  even balance between Black and White.

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Out of Balance
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Histogram

• A histogram is a form of bar chart showing the
  distribution of brightness in an image. Many
  current digital cameras have the ability to
  display the Histogram of an image when reviewing
  them.

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Histogram Example 1
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Histogram Example 2
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Histogram Example 3
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