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
A Poke in the Eye (With a Sharp Stick) A Poke in the Eye (With a Sharp Stick) A Poke in the Eye (With a Sharp Stick) is the title of the first show in what later became the iconic "Secret Policeman's Ball" series of benefit shows for human rights organization Amnesty International, although it pre-dated by three years the first show to bear that name.. The film of the show was titled "Pleasure At Her Majesty's" which is sometimes mistakenly thought to be the title of the actual benefit show. The landmark 1976 show starring the Monty Python, Beyond The Fringe and The Goodies teams and other top