New answers tagged

1

Pretty much all answers which focus on movement of the eye causing blur (something a digital camera does not have to deal with) are wrong. The brain has absolutely no problem processing images in low-light at speed. The answer is all to do with the fact that the eye is not a camera. Much of the old-school theories which where based on the fact that the eye ...


5

The differences at the photoreceptor level have been addressed by others. The mechanical restrictions of the visual system were shortly hinted at by @gilhad et al., but deserve more attention in my opinion. First off, in darkness we cannot focus on an object and our eyes will move. And even when we focus on a specific point there is always movement of the ...


7

There's probably a theoretical capacity to do so. The brain is amazingly good at signal processing, and could probably pull off such a summation. However, there is a limit. You have to hold very very still for it to work. Go take one of the time lapse pictures, like anongoodnurse's answer posted. The shutter is open for quite some time (her picture ...


13

The simple answer is, that eye is not constructed such way. The eye have much more "pixels" than "links" to the brain and sends in "preprocessed" image. Moreover the the eye is constantly moving and scanning the "area of vision" and the body and head are supposedly also moving (willingly or not - nobody can freeze totally) so longer accumulation of data ...


29

For simplicity's sake, let's really reduce this to something like photography. A camera's aperture can stay open indefinitely, allowing the plate (or whatever is receiving and recording light) to "collect and save the effect of photons" over time, if you want to phrase it that way. That allows a camera to make images that our eyes never can, for example, of ...


2

What I believe you are referring to, is the phenomenon by which the camera adjusts light exposure by adjusting aperture. We can also do this, but it happens very fast. Go from a dark room to a brighter room and you will be blinded, but that effect soon subsides, and vice-versa. The pupil opens up in a dark room and production of visual purple or Rhodopsin ...


2

Birds find their niches based on many reasons. Their choice is based on primarily resource availability, predation risk, and competition. Keep in mind there are variations among species, most birds like to forage for food at a hight safe enough to avoid ground predation, at the same time to be able to see and find food without much competition. Therefore ...


3

Looking at it completely in terms of evolutionary pressure: 1.1 The whole idea of binocular vision for humans, (and some other species) is depth perception. If you suggest continuous, alternate winking, the cognition of the individual would be seriously affected. The 'wink as needed' mechanism (assuming all other visual processes are as they have evolved ...


-2

Tears contain an important hormone that kills bacteria. Closing eyelids during sleep allows a prolonged contact between the cornea and tears killing resistant bacteria in the process. The action of the tears during blinking is not sufficient to completely get rid of the foreign bodies in the eyes. Closing eyelids gives the tears a capacity to accumulate ...



Top 50 recent answers are included