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How does a camera work?

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Quick answer

A camera works by focusing light through a lens onto a sensor (or film) that records the image. The lens bends incoming light to form a sharp picture, and the sensor measures the light's brightness and color at each point to capture the scene.

Step by step

  1. A lens bends light to focus a sharp image onto the sensor.
  2. The aperture controls how much light enters; the shutter, for how long.
  3. A digital sensor has millions of pixels that measure light and color.
  4. The captured values are saved as a digital image file.
  5. Focus, exposure, and lens choice shape how the photo looks.

People also ask

How does a digital camera capture an image?
Light focused by the lens lands on a sensor whose millions of pixels measure brightness and color, and those readings become a digital photo.
What does the aperture do?
It's an adjustable opening controlling how much light enters and how much of the scene is in focus (depth of field).
Why do photos blur?
Either the focus is off, or the subject or camera moved while the shutter was open long enough to smear the light.
What do aperture and shutter speed do?
Aperture sets how wide the lens opens (light + depth of field); shutter speed sets how long the sensor is exposed.
How is a camera like the eye?
Both focus light through a lens onto a light-sensitive surface — a sensor in a camera, the retina in an eye.

Part of the guide: Everyday Machines →