Through the thin layer of crystal clear water, can be seen the sand and gravel which is partially covered by algae. The uneven flow of water, due to irregular surfaces over which tumbles under the action of gravity, deforms like a lot of lenses and unevenly illuminates the underwater riverbed.
The picture was captured with a Nikon D40X camera and Nikon 55-200mm VR AF-S f/4-5.6G ED lens, using the following settings: exposure time – 1/169 seconds, ISO – 400, focal length – 190, F- number – 6,3.