Considered to be the father of modern Optics.
Al-Haitham was one of the most eminent physicists whose contributions to optics and the scientific methods are outstanding.
He invented the first pin-hole camera after noticing the way light came through a hole in window shutters. The smaller the hole, the better the picture, he worked out, and set up the first Camera Obscura (from the Arabic word qamara for a dark or private room).
Al-Haitham conducted experiments on the propagation of light and colours, optic illusions and reflections. He examined the refraction of light rays through transparent medium (air, water) and discovered the laws of refraction. He also carried out the first experiments on the dispersion of light into its constituent colours.
Al-Haitham wrote on refraction, reflection, focusing with lenses and other topics. He was the first person to give an accurate account of vision and stated that light comes from the object seen to the eyes - described accurately the various parts of the eye and gave a scientific explanation of the process of vision. His book 'Kitab-al-Manazir' was translated into Latin in 1270 as Opticae thesaurus Alhazeni libri VII, as also his book dealing with the colours of sunset. He dealt at length with the theory of various physical phenomena such as the rainbow, shadows, eclipses, and speculated on the physical nature of light.
Al-Haitham also contributed to mathematics - developed analytical geometry by establishing linkage between algebra and geometry - and in Physics he studied the mechanics of motion of a body and was the first to propose that a body moves perpetually unless an external force stops it or changes its direction of motion.
During the Middle Ages al-Haitham's books on cosmology were translated into Latin and other European languages. He also wrote a book on the subject of evolution: the ideas contained in that book are worth reading and useful even today.
Al-Haitham known in the West, as Alhazen was born Abu Ali Hasan Ibn al-Haitham at Basra. He travelled to Egypt and then to Spain where he spent most of his life and there he conducted research in optics, mathematics, physics, medicine and development of scientific methods.
Compiled by:M. Nauman Khan / Ghulam Mohiuddin