If you know me, you know that I am nuts about photographing spiral staircases. The Hotel D’Orsay in Paris has two, one with an elevator running up the middle, and the main stairs, which has five flights in a narrow spiral formation.
This kind of staircase tends to be harder to photograph than meets the eye. First, they are rarely well lit. This means a long exposure if you are stopping the lens down to get enough depth-of-field for most of the spiral to be in focus. The problem with a long exposure is that this kind of old staircase is usually they are rickety and transmit vibrations. If anyone comes up or down the stairs, they are likely to spoil your exposure just by walking past.
Another issue is holding the camera steadily above the stair for a straight shot down. You need a good tripod and steady nerve, but you can usually brace the tripod against the railing to make this possible. To make life easier and avoid all the trouble, simply shoot the spiral staircase with your iPhone!