David Hockney Hypothesis on the use of lenses and mirrors in the history of art.
The theory proposes that since the 15th century, lenses, like those made in Delft, Holland at the end of the 1400s, were perhaps used by artists to get a more realistic view in their painting.
Some paintings, David Hockney argues, with strong contrast suggest strong sunlight on the scene. And a strong sunlight was necessary for the lenses to work.
Moreover, fine details like fine drapery designs and complicated drawings like a hanging chandellier would have been impossible to draw so precisely by a painter.
But I love Hockney's conclusion: to be painterly again. He proposes to do something incredible in our digital era so obsessed by photograpy-like pictures: to go out and draw the world from real life again. Free from the "perspective" trap and photo realistic paintings.