• Question: if the camera lens is circle why do the pictures come out square?

    Asked by alexcarrx to Clare, Glafkos, Paul, Samantha on 9 Mar 2015.
    • Photo: Samantha Terry

      Samantha Terry answered on 9 Mar 2015:

      Hi, that is a superb question. I think the answer is not science-related but to do with what we as consumers are pushed towards…

    • Photo: Glafkos Havariyoun

      Glafkos Havariyoun answered on 9 Mar 2015:

      The reason for using circular came lenses is a convention from old film cameras! Have you ever seen a film before? They were divided in rectangular regions and the lens is used to direct and focus light on to that sensitive rectangular region! This convention has carried on to conventional digital cameras.

    • Photo: Clare Devery

      Clare Devery answered on 9 Mar 2015:

      Yeah, I think Samantha is right! The lens is round because it’s simpler to manufacture like that and because a lens needs to behave the same way when rotated.
      Old style film was rectangular because it was convenient to make in that shape and because paper has always been a rectangular shape. It’s just convention. Round paper and round film would be a nightmare to produce, and very wasteful!
      As Glafkos has said, digital technology just adopted what was already the norm.

    • Photo: Paul Booker

      Paul Booker answered on 9 Mar 2015:

      Although the image coming through the lens will still be circular, the area that detects the light (which used to be film and now is a usually an electronic sensor) is rectangular shaped. This is probably because it’s easier to manufacture lots of rectangular shaped bits of film/sensors, whereas making lots of circles wastes a lot of material as they don’t tessellate.

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