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In humans, the pupil is circular, but its shape varies between species; some cats, reptiles, and foxes have vertical slit pupils, goats and sheep have horizontally oriented pupils, and some catfish have annular types. [3] In optical terms, the anatomical pupil is the eye's aperture and the iris is the aperture stop.
The effect of spherical aberration (a fourth-order aberration) increases as the fourth power of the pupil diameter. Doubling pupil diameter increases the spherical aberration component by a factor of 16. [7] Thus, a small change in pupil size can cause a significant change in spherical aberration.
The pupil of the human eye can range in size from 2 mm to over 8 mm to adapt to the environment. The human eye can detect a luminance from 10 −6 cd/m 2, or one millionth (0.000001) of a candela per square meter to 10 8 cd/m 2 or one hundred million (100,000,000) candelas per square meter.
Much of the scientific work on optography was performed by the German physiologist Wilhelm Kühne.Inspired by Franz Christian Boll's discovery of rhodopsin (or "visual purple")—a photosensitive pigment present in the rods of the retina—Kühne discovered that, under ideal circumstances, the rhodopsin could be "fixed" like a photographic negative.
A camera lens adjusted for large and small aperture. The visible opening is the entrance pupil of the lens. The apparent location of the anatomical pupil of a human eye (black circle) is the eye's entrance pupil location. The outside world appears to be seen from the point at the center of the entrance pupil.
The human eye, showing the iris and pupil. In 1802, philosopher William Paley called it a miracle of "design."In 1859, Charles Darwin himself wrote in his Origin of Species, that the evolution of the eye by natural selection seemed at first glance "absurd in the highest possible degree". [3]
Ever wonder why seeing pictures of adorable puppies turns humans into piles of emotional mush? Stanford University Professor Robert M. Sapolsky looked into the phenomenon and came up with some ...
The pupil function or aperture function describes how a light wave is affected upon transmission through an optical imaging system such as a camera, microscope, or the human eye. More specifically, it is a complex function of the position in the pupil [ 1 ] or aperture (often an iris ) that indicates the relative change in amplitude and phase ...