< Modern Photography

The image sensor of a modern, digital camera replaces traditional analog film as the camera's recording medium.

In comparison to film they are:

  • Much cheaper to operate, essentially free versus significant costs for film purchase and development.
  • Essentially unlimited, given the widespread availability of cost-effective, light and portable digital storage today.
  • Almost always color, rather than some being in color, and others being black and white.
  • More flexible during shooting, allowing the photographer to change desired recording medium sensitivity between every shot without physically ejecting and replacing a roll of film
  • Far more sensitive than commercially available film, with ISO ratings of 12800 not uncommon (at the close of the 20th century it was generally hard to find ISO800 film across much of the world, ISO400 being the highest typically acquirable sensitivity, sometimes only ISO200)

However, they also have problems:

  • Burn-out: there is a very strong tendency for bright areas such as sun-lit clouds to 'burn out' and become a solid block of perfect white, resulting in a loss of detail.
  • Lower dynamic range than film: the difference between the darkest shade before black and the brightest shade before white that can be recorded within a scene is known as the dynamic range. Film generally surpasses digital image sensors in this regard, though they are rapidly improving and with technology advances currently announced they will exceed film in the near future.

Most importantly, the image sensor sizes are expressed in terms of pixels, eg. 8688×5792 pixels. It is not possible to determine the pixel count from the sensor format, and vice versa, though there is some relation: larger sensor sizes tend to have larger pixel counts. Because large modern pixel numbers can be hard to remember, the industry has standardized on megapixels, or the number of total pixels divided by 1,000,000 (one million). For example, the Canon 5DS has a resolution of 8688×5792 pixels, which is equal to 50,320,896 pixels in total, or roughly 50.3 megapixels.

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