I bet no one knows enough to answer THIS question... !

Discussion in 'Digital Photography' started by Scotius, Jul 15, 2010.

  1. Scotius

    Scotius Guest

    Why is it that camera lenses are round, but pictures are
    square? Hmmm? Tell me that ya' smarteys!
    Scotius, Jul 15, 2010
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  2. Scotius

    Robert Coe Guest

    : Why is it that camera lenses are round, but pictures are
    : square? Hmmm? Tell me that ya' smarteys!

    IOW, Will we help you cheat on your take-home physics exam?

    Ans.: No
    Robert Coe, Jul 15, 2010
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  3. Apart from the fact that they are usually rectangular, not square,
    round photos would waste a lot of film and paper.
    Chris F.A. Johnson, Jul 15, 2010
  4. It's a mystery that'll never, ever be explained.
    John McWilliams, Jul 15, 2010
  5. Scotius

    krishnananda Guest

    The Nikon 8mm 180-degree fisheye produces a circular image on
    rectangular film, as do other non-full-frame fisheyes.

    But a much more important question is why are hot dogs sold in packs of
    10 but hot dog buns are sold in packs of 8?

    In philosophy this is known as the "Hot Dog Dilemma".
    krishnananda, Jul 15, 2010
  6. Scotius

    Rich Guest

    It is a waste, but some rectangles are less sensible that other. Like
    how 3:2 is inferior to 4:3.
    Rich, Jul 15, 2010
  7. Roger that! There is one theory that the average klutzy BBQer will drop
    two in front of the guests, and have to dispose of them in the garbage
    instead of putting 'em back on the grill.
    John McWilliams, Jul 15, 2010
  8. Scotius

    Twibil Guest

    And this is known as "Marketing".
    Twibil, Jul 15, 2010
  9. Scotius

    Twibil Guest

    Another theory posits that many klutzy BBQers own large dogs.

    http://www.flickr.com/photos/[email protected]/3541701218/
    Twibil, Jul 15, 2010
  10. And just the right number! Two.....

    john mcwilliams

    "Nobody in football should be called a genius. A genius is a guy like
    Norman Einstein." - Football commentator and former player Joe
    Theismann, 1996
    John McWilliams, Jul 15, 2010
  11. Scotius

    Nervous Nick Guest

    Because they fit into the frame better.
    Nervous Nick, Jul 15, 2010
  12. Scotius

    Bowser Guest

    It was also the question asked by the Bulletproof Monk. His answer: because
    they do.
    Bowser, Jul 15, 2010
  13. Scotius

    Bowser Guest

    Horribly simple:

    Because the earth is round, we need round lenses to see it. But because
    paper is flat and rectangular, we need cameras and stuff to process the
    round images into flat rectangular images so we can see them. Same goes for

    I'm really surprised you even had to ask.
    Bowser, Jul 15, 2010
  14. Scotius

    whisky-dave Guest

    It's because trees are round which is what we use to make paper,
    but the paper we print them on is square (or rectangle).
    It's a government conspiracy that's been going on since the dawn of
    whisky-dave, Jul 15, 2010
  15. Scotius

    Scott W Guest

    You could make a square lens, but then you would need to take round
    photos and that would be a pain.

    Scott W, Jul 15, 2010
  16. Scotius

    ray Guest

    1) the pictures taken by most cameras I'm familiar with are rectangular
    rather than round.

    2) it's a lot easier to make a round lens.

    3) it's a lot easier to make film and/or sensors rectangular.
    ray, Jul 15, 2010
  17. Scotius

    Peter Guest

    I'll answer hen I get a round to it.
    Peter, Jul 15, 2010
  18. Scotius

    ray Guest

    I have some extra round toit's I can spare - how many do you need?
    ray, Jul 15, 2010
  19. Scotius

    BF Guest

    What a bunch of worthless answers.
    BF, Jul 16, 2010
  20. Scotius

    krishnananda Guest

    You've got it in a nutshell. If it were possible to mount a lens
    designed for APS-C sized sensors on a "full frame" camera you'd get
    exactly that vignetting. On a view camera if you mount a lens with an
    image circle big enough for 4"x5" on an 8"x10" camera you'd get a
    perfectly circular image, suitable for cutting out with scissors and
    putting in a round frame.

    Ultra wide angle large-format lenses have an image circle much larger
    than the active film area. This gives them the ability to
    rise/fall/shift so much the regular bellows has to be replaced with a
    "bag" bellows, as the front standard's range of motion would seriously
    damage a pleated bellows. These lenses are extremely expensive.

    As far as manufacturing is concerned, optical glass is extruded under
    very tightly controlled conditions, then sawn into lens blanks which are
    then ground into convex/concave circle-based curves. Aspheric elements
    are either pressed into ceramic molds under extremely high pressure, or
    are CNC machined, like "Varilux" eyeglasses lenses.

    Unlike aluminum, which can be extruded into very complex shapes with
    sharp corners, glass is technically a very viscous liquid. As such it
    cannot be extruded into hard-edged/sharp-corner shape. The extruded
    glass "salami" (yes, that's what it's called) _could_ be machined into a
    square/rectangular shape. However, that would increase costs by more
    than an order of magnitude and would serve no optical purpose. The
    negative mask at the back of an SLR's mirrorbox does a virtual version
    of just that.

    Fiber-based paper can be made in any shape or thickness required.
    However, this requires using the antique mould-made process where the
    paper pulp is pulled onto the laid and then pressed entirely by hand.
    There are some beautiful Gum Bichromate, Platinum, and Palladium prints
    done on hand-made 300 lb. deckle-edged paper. For mere mortals, paper
    pulp is carried by a web belt through progressively narrowed gaps
    between rollers, compressing the fibers, driving out the water, and
    applying the surface finish. This is an industrial process and as such
    is governed by cost. The cost of mould-made paper produced in the
    tremendous quantities required for consumer use would bankrupt the
    Sultan of Brunei.

    Many of Eugene Atget's photos of paris were taken with the front
    standard of his glass plate camera at maximum rise. This vignetted the
    top corners of the image where the image circle failed to fill the
    entire frame. Didn't bother him.
    krishnananda, Jul 16, 2010
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