Caustic Network in the Dead Sea
December 29, 2013
Photographer: Menashe Davidson
Summary Author: Menashe Davidson
The photo above shows a caustic network observed in the Dead Sea, Israel. It was taken at the Bokek resort area on January 15, 2012. Caustic networks result from refraction of sunlight in undulating water surfaces. They're typically best seen when sunlight is strong, the water is clear, waves are small and depths are shallow -- less than about 7 ft (2 m). In essence, the water's surface behaves like a series of positive and negative lenses; sunlight is alternatively brought into and out of focus. The brighter linear regions on the bottom are in rough focus while darker regions are out of focus (see photo at left). Because waves propagate across the water, the caustic network will as well. A relatively bright seafloor, salt sediments in this case, seems to enhance the visibility of a caustic network.
Photo details: Top - Camera Model: NIKON D80; Focal Length: 18.0mm (35mm equivalent: 27mm); Aperture: f/7.1; Exposure Time: 0.0005 s (1/2000); ISO equiv: 400. Inset - Same except Focal Length: 125.0mm (35mm equivalent: 187mm); Exposure Time: 0.0008 s (1/1250).