Spiral staircase in blue

This is the beautiful spiral staircase in the 17th century Queen's House in Greenwich, England. No tripods were allowed, so I had to compromise between shutter speed, aperture, and ISO to minimize noise, capture enough depth of field, and still have a sharp picture. I took this several years ago with the Canon 5D Mark II, and noise was a significant issue then. I photographed the staircase with several wide angle focal lengths, and in the end I liked them all -- 14mm, 16mm, 24mm, and this shot that was taken with a 15mm fisheye. Note that fisheye lenses curve vertical and horizontal lines, but when you photograph something already curved, the lens can't make it more round. My settings for this shot were 1/20, f/8, and 800 ISO, and I used tungsten white balance which gave this image the blue/cyan cast. I felt I could get away with such a slow shutter speed because of the extreme width of the lens; movement isn't magnified with an ultra wide angle.