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Foreshortening - mirror vs photo/video

  1. Dec 29, 2007 #1

    Is there more foreshortening when I look in the mirror than when I look at a video or photograph of myself.

    For example, if I am naked, or with bare legs, and I walk towards a mirror, will my knees look lower to me than if I watch a video of myself walking towards the camera? (assuming the camera is at my eye level.)

    And if so, which of these two perspectives more closely represents reality? / Represents what another person would see as I walk towards them?

    Thank you.
  2. jcsd
  3. Dec 29, 2007 #2

    Doc Al

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    Staff: Mentor

    I don't know anything about distortions introduced by video, but your image in a vertical plane mirror will not be foreshortened. If you are x feet from a plane mirror, your image (identical in size to the original you) will appear to be x feet on the other side of the mirror (that is, 2x feet away from you).
  4. Dec 29, 2007 #3
    Thanks Doc Al,

    I was thinking that if my image in the mirror is 2x feet away, but the angle from my eyes to the reflection of my knees would still be equivalent to the angle at x feet, then that might make my knees seem lower?

    Or is the angle from my eyes to my knees in the mirror less steep than it would be if I was looking at my identical twin at x feet? Because my knees are effectively 2x feet away?
  5. Dec 29, 2007 #4

    Doc Al

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    Staff: Mentor

    Looking at your image in the mirror (when you're x feet from the mirror) is exactly like looking at an identical twin standing 2x feet away.
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