Spiral Stairs, Alcatraz
_I made this image on February 3, 2012 on the island of Alcatraz in the San Francisco Bay. Alcatraz was a fortress around the time of the Civil War. It also housed Civil War prisoners as early as 1861. Alcatraz remained a military prison until 1933 when it officially became a federal prison. It was closed as a a prison on March 21, 1963. I made the image with 2 Sigma DP1 digital cameras mounted next to each other on a panoramic device I constructed which allows the cameras to rotate up or down around what is called the entrance pupil of the lens. This enabled me to tilt the cameras slightly downward to make one part of the image, then straight ahead, and then upward to make the three parts of the image. I blended the parts of the image together using a computer program called Panorama Tools Graphic User Interface (PTGUI for short). The exposures were 2.5 seconds at f/8 (ISO 50). You can see the image in the format you prefer by clicking on one of the following: parallel, cross-eyed, or anaglyph (red/cyan glasses).