• Question: How do cameras work?

    Asked by to Daren, Lynne, Phillip, Simon on 21 Jun 2014. This question was also asked by .
    • Photo: anon

      anon answered on 21 Jun 2014:

      The films in old fashioned cameras are covered in a silver salt which, when exposed to light, decomposes and deposits a silver solid on the surface. That’s why, if you look through a film, it’s in negative – the areas with the most light have the most silver deposited on them, whereas the dark areas have none.

      In modern, digital cameras, the light hits a semiconductor rather than a film. This semiconductor measures how much light is hitting it and assigns each pixel a number.

      The computer in the camera then interprets the number and reassembles your picture. If you look at any screen under a microscope you’ll see that it’s made up of red green and blue pixels, which combine in different amounts to give every colour possible. (believe it or not, this is what your phone screen looks like magnified about 10 times http://www.extremetech.com/wp-content/uploads/2012/06/lcd-screen-under-a-microscope-640×353.jpg)

    • Photo: Lynne Thomas

      Lynne Thomas answered on 22 Jun 2014:

      Jenny has given a really nice description of how the recording of images has changed as we moved to digital. Of course in cameras there are also lenses which allow us to focus on things at different distances and to effectively zoom in on things. These days we can have two types of zoom, an optical zoom which is done with the lenses and a digital zoom which is a consequence of the many mega pixels we now have in our digital cameras. When you use an optical zoom, the picture remains of the same quality but digital zooms reduce the resolution of the image.

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