Optics of David Hockney

I went to a lecture at the University of Arkansas about four years ago on optics in the history of art. I knew of the camera obscura, so I am not really that shocked. Hockney figured out from the small amount of time, in ten to twenty years, during the early 1400's that all painters and artists had drastically improved in linear perspective and detail through the power of optics. I find it very fascinating still. I remember of the lecture of how the fabric in one painting was blurred in the original and that the eye doesn't go out of focus, especially when you are focusing on detail. However, I understand the when using a model or a number of different models you would need to basically outline them and have them rest, and then have them go back to the same position as before. There is also great detail in alot of the paintings claiming to use lenses, however, in the film, when Hockney had the images reflected on the canvas or paper, it all seemed blurry, to where you could maybe trace the outline, but the details are so sharp that I don't think that all of it could be traceable. It does give alot of artists starting out the hope of perfecting their craft, but at the same time, it is still tracing and that's why alot of artist, when photography came in to play, went back before the science of glass and mirrors. To more of and impressionistic and expressionistic style of painting.