Has anyone seen or even used the Camera Lucida tool that is advertised on the ' drawlucy.com ' web site? It looks kind of interesting, particularly if you want to draw anything directly onto your substrate or a drawing reference book. I was thinking it could reduce the number of steps needed to get your reference picture onto your substrate (ie: no tracing paper etc required). It also allows you to enlarge and keep perspective. Just asking, as not actually sure how useful in reality this would be.