Santo Antonio Caves in Portugal
September 19, 2012
Photographer: Andre Goncalves
Summary Author: Andre Goncalves; Jim Foster
The photo above features the Santo Antonio Caves in the Aire and Candeeiros Mountains near Leiria, Portugal. This cave complex was discovered in 1955 by a five-year-old boy who was chasing a bird and saw it fly through a small hole on the mountainside. The Santo Antonio Caves are believed to have formed over 50,000 years ago and are renowned for their great hall and glittering ponds, filled with stalactites and stalagmites. Artificial lighting allows visitors to witness beautiful reflections, such as shown here where the light reflects off the undisturbed water surface. Smooth, shiny surfaces reflect light in a very predictable manner -- light hitting a surface will bounce off at the identical angle it entered. This is referred to as specular reflection. Note that the reflected interior of the cave is slightly darker than the actual cave. Only at an incidence angle of 90 degrees is the reflectivity of water 100 percent. Photo taken on August 21, 2012.
Photo details: Camera Maker: Canon; Camera Model: Canon EOS 1000D; Lens: EF-S18-55mm f/3.5-5.6 IS; Focal Length: 18mm; Aperture: f/3.5; Exposure Time: 0.100 s (1/10); ISO equiv: 800; Exposure Bias: none; Metering Mode: Matrix; White Balance: Auto; Flash Fired: No; Orientation: Normal; Color Space: sRGB; Software: Adobe Photoshop CS6 (Windows).