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
The Stone Flower (1946 film) The Stone Flower (1946 film) The Stone Flower () is a 1946 Soviet fantasy film directed by Aleksandr Ptushko. It is an adaptation of Pavel Bazhov's story of the same name, in turn based on Ural region Russian folklore. It also incorporates plot elements from the stories "The Mistress of the Copper Mountain" and "The Master Craftsman". "The Stone Flower" was theatrically released by Mosfilm on 28 April 1946. It was the Soviet Union's first color film shot on Agfacolor negative film seized in Germany, and was entered into the 1946 Cannes Film Festival. It was a success at the