Diaphragm (optics) curved blades improve the roundness of the iris opening. In a photograph, the number of blades that the iris diaphragm has can be guessed by counting the number of diffraction spikes converging from a light source or bright reflection. For an odd number of blades, there are twice as many spikes as there are blades. In case of an even number of blades, the two spikes per blade will overlap each other, so the number of spikes visible will be the number of blades in the diaphragm used. This is most apparent in pictures taken in the dark with small
Diana Vreeland: The Eye Has to Travel Diana Vreeland: The Eye Has to Travel Diana Vreeland: The Eye Has to Travel is a 2011 documentary about the life and career of Diana Vreeland, a fashion legacy famous for her time at "Harper’s Bazaar" and "Vogue". The film was directed and produced by Lisa Immordino Vreeland (Diana’s granddaughter-in-law), Bent-Jorgen Perlmutt, and Frédéric Tcheng. It premiered at the 2011 Venice International Film Festival and the Telluride Film Festival. It has a total running time of 86 minutes, and can be seen with English, French, and Italian subtitles. The film features recorded audio and filmed interviews of Vreeland, as well