Why can I see sharply through a very little hole?

  • Thread starter kompabt
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  • #1
(I have myopia.)
  • #2
Google on pin-hole camera for an explanation of the optical effect. Pin-hole cameras are slow because they let very little light through, and the images they make are a bit soft.

As for your eyes, by restricting the angle of incidence in incoming light (looking through a pin-hole) you're minimizing the errors in your eyes' lenses. You may have noticed that when the light is dim and your pupils dilate as a result, your vision gets even worse than in daylight. This is typical.
  • #4
While reduced spherical aberrations play a role, a smaller aperture results in less blurring for objects that are not in focus. I hope this picture illustrates the effect clearly enough:


This is also why photographers use smaller apertures to get a larger depth of field, or large apertures for a narrow depth of field.

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