Why did artists use pinhole cameras during the renaissance?
... first one they came up with... someone noticed in a darkened room the keyhole letting in a light pattern on the opposite wall. Voila! the first discovered camera projection.
The pinhole camera was used during the renaissance for several purposes including astronomy, art and scientific research. It was one of the tools of advanced technology at the time. Visit http://photo.net/learn/pinhole/pinhole for more information.