Saturday, December 19, 2009

Why does light get stretched when reflected off water?

Here's a couple of photos that illustrate how light reflects off the water.

In the first, the lights are 'stretched'. Note that the lightning bolt also casts a reflection off the water in the same way as the apartment and street lights.

In the second pic, the light sources are not stretched:


So what causes the difference in the way water reflects off the water? Use of a circular polariser? The stillness of the water? The angle the picture is taken?

I suspect the relative angle is important. The first photo was taken of buildings at least 200m away, the second was taken of trees some 30m away. I suspect the smaller the angle of the light source relative to the camera lens, the larger the apparent stretching of the light across the water.

If this is true, this is bad. In order to get an unstretched reflection of lightning off the water, the photo must be taken from close quarters!

3 comments:

  1. It's because of the ripples on the water.

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  2. hi there! great photos, thanks for refering my humble blog :)

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  3. No problem Luis! Your blog is great esp because you are at a point where we hope to get to in the near future!

    Hmm..@Stephen..so the ripples cause the elongation of light? In that case you'd only really be able to get reflections off still lakes....or pools....

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