| Author | Thread |
|
|
12/05/2006 01:27:24 PM · #1 |
I find it interesting to know why something looks good, not just that it does look good. Since a camera is nothing more than a mechanical eye I thought it might be interesting to glean some information about how and why the eye sees light and colors.
This little article nicely explains rods and cones. Rods for light reception, cones for color reception.
This article on color perception is linked from the above and is quite interesting in how we perceive color.
This daylight article discusses the visual perception of daylight.
Why would I geek out on eyes? I'm a "Why?" asker, it's my nature. Knowing this may (or may not) help in composition, lighting, color casting, etc, and it surely cannot hurt. And there is the possibility for me to glean some information about light and color that isn't obvious, something I can reproduce, and use to my advantage when composing a shot.
So I thought I would share, enjoy :) |
|
|
|
12/05/2006 01:39:59 PM · #2 |
Heres a question I always wonder about. We humans seem to find a rectagular shape more pleasing than a square - is that because our field of vision is rectangular when we look at the world. We also seem to prefer an off center subject, slighlty to the right or to the left. Is that because our nose is in the middle and we see things to one side a little bit better?
I am a cyclops and I find a square with the subject in the middle more comfortable than the typical rectangle with the rule of thirds placement. |
|
|
|
12/05/2006 01:48:16 PM · #3 |
While I agree with the "rules" of composition, I'd disagree they have much to do with the biology of our eye. If the rectangular view of the world was the root cause of our enjoyment of rectangles, I would think that a vertical rectangle would be appreciated even less than a square crop. That doesn't seem to be the case. And while we like off centered compositions, when you hold something to look at it, you pretty well hold it right in front of you, not to one side.
Just playing devil's advocate.
|
|
|
|
12/05/2006 02:08:09 PM · #4 |
| Sort of on the same topic... I've always wondered why a cat's pupils dilate so dramatically when they're "focused" on an object they're about to pounce on. From a photographical hypothesis, maybe it's to get a very sharp depth of field to really zero in on the target, and (to some extent) the brightness of the object is not as important? Anybody know? |
|
|
|
12/05/2006 02:21:52 PM · #5 |
Pupil dilation is part of the sympathetic response, commonly known as the "fight" response (as in fight or flight). I cannot tell you why this is the case though. It's not like personal experience tells me that my vision changes when my pupils dilate. I don't notice a shortening of DOF or anything like that.
|
|
|
|
12/05/2006 02:22:10 PM · #6 |
Originally posted by Telehubbie:
Sort of on the same topic... I've always wondered why a cat's pupils dilate so dramatically when they're "focused" on an object they're about to pounce on. From a photographical hypothesis, maybe it's to get a very sharp depth of field to really zero in on the target, and (to some extent) the brightness of the object is not as important? Anybody know? |
pupil dilation (mydriasis) takes place when the radial muscles (arranged like spokes) around the eye constrict. the radial muscles are innervated by the sympathetic nervous system.
pupil constriction (miosis) takes place when the circumfrential muscles constrict. The circumfrential muscles are innervated via the parasympathetic nervous system, which lead to constriction.
My guess at what is going on with the cat... aggressive actions (such as hunting/pouncing) are associated with activity of the sympathetic nervous system. Digesting food and resting, however, are associated with activity of the parasympathetic nervous system... i would assume that the cat's eyes will constrict when eating their prey and napping afterwards. |
|
|
|
12/05/2006 02:28:16 PM · #7 |
| Interesting responses, thank you. I knew I was thinking too much. |
|
|
|
12/05/2006 02:32:39 PM · #8 |
| At which stage should one consider upgrading their eye to L glass? |
|
|
|
12/05/2006 03:54:59 PM · #9 |
Originally posted by Telehubbie:
Sort of on the same topic... I've always wondered why a cat's pupils dilate so dramatically when they're "focused" on an object they're about to pounce on. From a photographical hypothesis, maybe it's to get a very sharp depth of field to really zero in on the target, and (to some extent) the brightness of the object is not as important? Anybody know? |
My guess is to act as a rangefinder/bombsight:
If the pupils dilate, then the DOF is very shallow. Once focused sharply on the target under these conditions, the degree of tension on the ciliary muscles required to shape the lens and bring the image into focus can be accurately translated into an exact distance to the target.
For humans, the preference for an off-center object is probably one of using our more pronounced binocular vision for a similar purpose, but using triangulation rather than DOF, since the distances involved are so much farther (rock/spear/arrow distance vs. pounce) as to make DOF a less-valuable factor.
I think it's easier to triangulate the distance to a target if it is slightly off-center, forming a scalene vs. isosceles triangle; in the latter case the apex (target) would be more likely to seem to recede to the horizon (vanishing point) making the distance to the prey less-certain.
Also, normal throwing motions tend to dictate aiming at a target more nearly 90 degrees from the way we are facing (think pitchers, quarterbacks, etc.) than ahead of us.
Message edited by author 2006-12-05 15:57:50. |
|
|
|
12/05/2006 03:55:27 PM · #10 |
Originally posted by jhonan:
At which stage should one consider upgrading their eye to L glass? |
When you get cataracts. |
|
Home -
Challenges -
Community -
League -
Photos -
Cameras -
Lenses -
Learn -
Help -
Terms of Use -
Privacy -
Top ^
DPChallenge, and website content and design, Copyright © 2001-2025 Challenging Technologies, LLC.
All digital photo copyrights belong to the photographers and may not be used without permission.
Current Server Time: 09/20/2025 07:03:59 AM EDT.
