Eli5:If the pupil expands and shrinks depending on light, why dosent our field of view change with the pupil?
In: 6
The pupil is just like the aoerture in a camera. It roughly surrounds the point at which on-axis light converges as it travels through the eye between the cornea (lens) and retina (like a camera CCD).
When the pupil contracts, it blocks out off-axis light (light that enters the eye on a path not directly between its source and the convergence point I mention above). Like in a camera, reducing off axis light darkens and sharpens the resultant image.
This is why people who wear glasses often don’t need to wear them on a bright sunny day. Their contracted pupils turn their eyes into pinhole cameras which produce sharper images.
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