| Actual Image
Looking through ..for Anna (68)
iris
![Gold Star Critiquer/Silver Workshop Editor/Gold Note Writer [C: 409 W: 41 N: 784]](http://i1.treknature.com/misc/g-s-g.gif) (2478) | Hello friends,
This and the next month are going to be hectic. But I cannot pass a single day without coming in and looking at this wonderful site. I am trying to take time marking posts so that I can come back and start critiquing as soon as I have logged in.
I think i rushed a bit too much, as i myself can see some Noise in the image.I have treated the shot and posted the same as workshop.Please do have a look.
Today I present for you a Common Myna. I try not to repeat species I have earlier posted. But in this case my earlier post of a Common Mynah was done with a Handycam. Even as I did the PP work on the shot, and was in a dilemma whether I should post the myna again, my early days of photography came back to me. That was a time when I had just found out for myself how much I liked photography as a hobby. And I was consumed by the intense desire to take photographs even when I knew I was not fully equipped with a still camera.
This post is also a dedication to someone who has found out for herself not so long ago, how exciting the world of photography can be. Mrs. Anna Eksteen
, this is for you…for the sheer enthusiasm and zeal that I see in you whether posting a photograph with well researched notes or while critiquing a post. To me it is all about the effort that we make to continuously learn and improve by remaining open to positive criticisms at the same time enjoying all of it to the hilt : ) I also remember reading you Anna about this frontal PoV interest you had when it came to birds.
I would not want to spend much time with notes on this often posted bird. They are available in abundance in this very site or alternatively please look up here . But what I would like to write about is The Avian Eye and Vision. Isnt interesting that most birds can turn their head 180 degrees whereas we are not programmed the same way.
This photograph was taken while I was trying to capture a cuckoo from our terrace. This bird just flew in and sat there on the parapet in front of me looking right through me. I was quite close to the bird and just started clicking. It was only later when I viewed that I noticed while its body was turned the other way with its plumage facing me, its head too was facing me giving me a frontal PoV.
The Avian Eye and Vision
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A bird's eye is very similar in its basic structure to a human eye. But with regards to their weight, the eyes make up a much larger percentage of the weight of the head in birds than in man, i.e. 15% for a common Starling but only 1% for man. This is partly because a bird's eyes are larger relative to its skull than a human's and partly because the skull is lighter, i.e. no heavy jaw bone and teeth.
A bird's eye is very tightly fitted into its skull and it is capable of very little movement, therefore birds can often be seen moving their heads in order to change their visual relationship to something. In most birds the eyes are placed much nearer the sides of the head than in humans. This gives the bird a greater overall field of view, but greatly reduces its binocular vision (the area in which both eyes can see an object).
In man, binocular vision is about 140 degrees out of a total of about 180 degrees. On the other hand in a bird like a pigeon though the binocular area is only 20-30 degrees out of a total field of vision of 300-340 degrees. In many raptors and owls the situation is different. In these birds, as in many insectivorous birds, binocular vision, important in making judgments of distance, is more necessary and so these birds have their eyes more towards the front of their heads. This is most evident in owls where the total field of view is reduced to about 110 degrees with a binocular vision of 70 degrees. This is why owls turn their heads to watch you walk past. An owl can turn its head through over 200 degrees but cannot move its eyes in its head at all.
The most important parts of the bird's eye are the eyelids, the cornea, anterior chamber, iris, lens, posterior chamber, the retina, pecter, optic nerve and sclera .
There are two sorts of light receptors in the birds eye. They are called 'rods' and 'cones'. Rods are better for night vision because they are sensitive to small quantities of light. There can be as many as 150 rods connected to a single nerve cell, this increases its sensitivity but reduces its definition, i.e. things look blurry. Birds have 5 pigments (humans have only 3) and they give them greater sensitivity to certain colours allowing them to see more different shades of some colours such as red than we can. The cones have special oil droplets on them which help filter the light, making them more sensitive to smaller ranges of colour. As they have five different sorts of oil filters the eyes of birds can often see a far more subtle world than we can. Sea birds such as the Procellariformes use red oil filters to cut out the blue light scattered up from the sea. This makes it easier for them to discern small objects floating on or near the surface
Thanks for the visit…
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Ref:
http://www.earthlife.net/birds/vision.html |
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