Basic photography

Shutter speed:

  • How long your cameras sensor is exposed to light.
  • Measured in fractions of a second 1/30, 1/60, 1/250, 1/500
  • Fast shutter reduces motion blur BUT admits less light.
  • Fast shutter freezes time and uses less light.
  • Slow shutter captures movement and uses more light.

Aperture:

  • The diameter of the lens opening.
  • Expressed as a fraction of focal length (f-number) f/2 on 50mm lens= 25mm aperture.
  • Big f-number means stopped down aperture (small hole).
  • Under exposed pictures are dark and shadows turn black.
  • Over exposed pictures are white, loosing a lot of detail and there’s a loss of contrast (shadows).
  • A low f-number = High aperture, smaller the ‘f’ the less light.
  • A large aperture gives more light but a shallow ‘Depth of field’.

Depth of field:

  • A range of distance that is acceptable ‘in focus’.
  • Small = large depth of field
  • Large = shallow depth of field ( background blurred) e.g. portraits.
  •  Image sharpness decreases away from the focal plane.
  • As your aperture increases, the points in which the focal plane will produce an acceptably sharp image also increases.
  • Using ‘aperture preview’ mode you can temporarily stop-down the aperture and see the true effect.

Exposure:

  • The same exposure can obtain with a shutter interval twice as long and the aperture area half as big.
  • Aperture (f/16) not a lot of light.
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