Who was the first man to take a photograph?

Joseph Nicéphore Niépce did, in 1826. Giovanni Battista DELLa Porta in his great work Magiœ Naturalis of 1558 does lay some emphasis on the use of the camera obscura (literally dark room in Latin), a tent or room with a small hole in one wall which optically projects an upside-down image of the scene outside to the opposite wall (all modern photographic cameras are simply small camera obscuras), but DELLa Porta considered the camera obscura primarily an instrument of entertainment, and certainly did not invent chemical Photography. That had to wait nearly three more centuries.

Linear perspective had come into widespread use in Italy in the 15th century. The camera obscura aided artists in creating more precise depictions. Sketches made from the projected image in a camera obscura had more exact spatial perspective because a three dimensional scene was accurately projected onto a two dimensional surface. The resulting sketches might, in a considerable stretch, be called "photographic" insofar as they were made from an optical projection, but a true chemical photograph (literally light writing, from the Greek) had to wait until the summer of 1826, when Joseph Nicéphore Niépce is credited with producing the world's first chemical photograph using a camera obscura.

Niépce had made photographic negatives on paper with a camera as early as 1814, but was not able to make them permanent. The first permanently fixed photo was that of his 1826 view through his window at Gras.