Why do rainbows do that?

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AliB

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One for the physicists.....discussing in the office this morning that when you photograph a rainbow, the sky colour inside the rainbow is very different to the sky colour outside the rainbow yet our eyes don't seem to see the difference nearly as much as it shows up in a pic.

So what's the reason? :)
 
fantastic! Thanks for that.

We were postulating that the effect seems to be recorded more by a camera than by the naked eye, any ideas if that's true or how it could be caused if it is?
 
AliB said:
fantastic! Thanks for that.

We were postulating that the effect seems to be recorded more by a camera than by the naked eye, any ideas if that's true or how it could be caused if it is?
Click to expand...

Remember that the camera records faithfully everything that enters it. There is no interpretation, all you have is EM radiation of varying wavelengths (light) that excite electrons in the sensor, create a small electric current and record the stimulation as the image.

Your eye on the other hand is much much cleverer as it works in conjunction with your brain to produce a "useful" image, rather than what we necessarily see. There are numerous mechanical weaknesses with the eye, an unfortunate consequence of evolution. In particular you have a blind spot smack in the center because the photo sensitive celles in your retina are on backwards. The nerves exit infront of the retina, meet up in the middle, and then pass through the back of the eye.

The brain adds a substantial ammount of information to the observed image, usually adding context. The brain sees what it wants to see. The best example I can think for this is the image I have linked to below.

grey_square_optical_illusion.png


Squares A and B are actually the same shade of gray. Open it up in photoshop, see for yourself. You simply can't see it for yourself because your brain interprets the image.

When aspects of an image look different in photos than in real life it's a case of the brain applying context. It sees what it thinks it should see.
 
I think your eyes just auto-expose the band out. Try 'not looking' at it at the periphery of your vision.
 
I'm with you guys :) As a photographer I kind of figure how a camera works but the folks in the office were wondering how they can look so different after I took some pics of a rainbow out the office window and apparently they looked more "different" between the colours inside and outside the rainbow that my colleagues were observing for themselves.

I know how light splits into wavelengths through a prism and did wonder of there was an element of polarisation going on as the wavelengths split.
 
another interesting point about a rainbow is it is transcendent..(i think this term is right..existing only for an instant adn only once)
only exists in one place at one time
not even in both your eyes
to do with the light rays and water droplets relativity
so the one (two?)you see is(are) unique for all time in a fleeting instant...everchanging
the one i see also is unique...but mine is yooneeker....
no it isnt
yes it is
blah blah
 
AliB said:
One for the physicists.....discussing in the office this morning that when you photograph a rainbow, the sky colour inside the rainbow is very different to the sky colour outside the rainbow yet our eyes don't seem to see the difference nearly as much as it shows up in a pic.

So what's the reason? :)
Click to expand...

I wondered that. Like this one.
rb2.jpg
 
Maybe it shows more in a picture because the natural response to a rainbow is to jack up the contrast to make it look more vivid :)

Interesting like there, thanks.
 
I did wonder if it was down to our eyes doing some evaluative metering?

Because we see a lot more in terms of field of view our eyes see more of the stuff outwith the rainbow while the camera sees a far more concentrated view and thus it looks more vivid.

I had not done any PP to the image and it was still on camera, just viewing on screen.
 
Oh, lol. My apologies, I really should have hit edit to see if it was still there.

I shall beg forgivness, and provide cake, if I can find any.
:coat:
 
Fantastic! Thanks Bob I'll share that round the office tomorrow and observe the puzzled expressions :)
 
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