Ranger Morgan kindly let us see the inside of the Point Reyes Lighthouse. Inside the lighthouse, we found a fresnel lens with an antique Swiss clock-like mechanism that rotated and generated the light. In its time, the system was something of a wonder, requiring technology and crafts people from several different nations. Think of the intracies of Swiss watch design combined with late Victorian optics.
This mechanism is no longer in use, have been replaced by a modern automated system.
I photographed the lighthouse mechanism with my digital fisheye lens, showing the spiral staircase (on the right of the image ) as well as the lens-and-clockwork mechanism. I used a tripod and a long exposure to stop the lens down for maximum depth of field.