Posts Tagged ‘eyeball’
Last Saturday, we featured a creative music video by the band James Wallace and the Naked Light that was shot entirely in one take in the reflection of a fan’s eyeball. It was a wonderfully simple video and an approach we hadn’t seen before in a music video.
But shortly after featuring that video, we were told that a similar idea had actually been done before by the Italian band K-Conjog, when they made the award-winning video for their song Qwerty. Read more…
This article started after I followed an online discussion about whether a 35mm or a 50mm lens on a full frame camera gives the equivalent field of view to normal human vision. This particular discussion immediately delved into the optical physics of the eye as a camera and lens — an understandable comparison since the eye consists of a front element (the cornea), an aperture ring (the iris and pupil), a lens, and a sensor (the retina).
Despite all the impressive mathematics thrown back and forth regarding the optical physics of the eyeball, the discussion didn’t quite seem to make sense logically, so I did a lot of reading of my own on the topic.
Using the human eye to control cameras isn’t a new idea — Canon used to offer eye-controlled focusing in its SLRs — but designer Mimi Zou‘s Iris concept camera takes the concept one step further by having the camera be entirely controlled by the eye. Shaped like a lens, the photographer uses the camera by simply looking through it. Focusing, zooming, and snapping photos are done by looking, narrowing/widening the eyes, and blinking (respectively).
Ever wonder what the f-number of your eyes are? It can easily be calculated using the human eye’s focal length (~22mm) and physical aperture size. Here’s what Wikipedia has to say:
Computing the f-number of the human eye involves computing the physical aperture and focal length of the eye. The pupil can be as large as 6–7 mm wide open, which translates into the maximum physical aperture.
The f-number of the human eye varies from about f/8.3 in a very brightly lit place to about f/2.1 in the dark. The presented maximum f-number has been questioned, as it seems to only match the focal length that assumes outgoing light rays. According to the incoming rays of light (what we actually see), the focal length of the eye is a bit longer, resulting in minimum f-number of f/3.2.
The article also notes that the eye cannot be considered an ordinary air-filled camera since it’s filled with light refracting liquid.
After taking a macro photograph of his own eye using a Samsung WB500 compact camera, Jarroseph was startled to find that the photograph showed his own face reflected in his eyeball. His face had reflected off the front of the lens, off his eyeball, and then into the camera!
Image credit: Photograph by Jarroseph and used with permission
Here’s a slow motion video showing a closeup look at the human eye, our amazing biological lens (and sensor). You might be surprised at how mechanical its movements are and how fluid the iris is. Another crazy fact is that we’re continually relying on “image stabilization” to see things clearly:
The visual system in the brain is too slow to process information if the images are slipping across the retina at more than a few degrees per second. Thus, for humans to be able to see while moving, the brain must compensate for the motion of the head by turning the eyes. [#]
To see a quick demonstration of this fact, try the following experiment: hold your hand up, about one foot in front of your nose. Keep your head still, and shake your hand from side to side, slowly at first, and then faster and faster. At first you will be able to see your fingers quite clearly. But as the frequency of shaking passes about 1 Hz, the fingers will become a blur. Now, keep your hand still, and shake your head. No matter how fast you shake your head, the image of your fingers remains clear. This demonstrates that the brain can move the eyes opposite to head motion much better than it can follow, or pursue, a hand movement. When your pursuit system fails to keep up with the moving hand, images slip on the retina and you see a blurred hand. [#]
Like with cameras, our built-in image stabilization can deal with head shake but not motion blur.
You might want to skip this post if you’re squeamish. A filmmaker named Rob Spence has successfully become a cyborg by replacing an eye he lost through a childhood accident with a wireless camera that transmits everything he sees to a computer. Spence believes that technology may soon reach the point where are be tempted to swap out their body parts for superior prosthetics. No word on when he’ll be able to apply Instagram filters to his eye camera photos.
(via Mail Online)
What if in the future, the human eye itself could be turned into a camera by simply reading and recording the data that it sends to the brain? As crazy as it sounds, researchers have already accomplished this at a very basic level:
In 1999, researchers led by Yang Dan at University of California, Berkeley decoded neuronal firings to reproduce images seen by cats. The team used an array of electrodes embedded in the thalamus (which integrates all of the brain’s sensory input) of sharp-eyed cats. Researchers targeted 177 brain cells in the thalamus lateral geniculate nucleus area, which decodes signals from the retina. The cats were shown eight short movies, and their neuron firings were recorded. Using mathematical filters, the researchers decoded the signals to generate movies of what the cats saw and were able to reconstruct recognizable scenes and moving objects. [#]
Basically, the scientists were able to tap into the brain of a cat and display what the cat was seeing on a computer screen. Something similar was accomplished with humans a few years ago, and scientists believe that in the future we may even be able to “photograph” human dreams!