Not extraordinarily unusual. All you have to do is align the focal plane of the lens with the camera sensor. Usually this is done with a metal flange of greater or lesser complexity. Here he just had to adapt the threads on the lens to the threads on the camera body. Twenty minutes in any well-equipped machine shop.<p>Modern lenses are very complicated, because they work to cancel out all sorts of subtle and troublesome distortions, but a lens can be very simple indeed. A Lensbaby[1] is just a single lens element attached to some stiff bellows.<p>And that's it.<p>You could hand it to Robert Hooke and he would nod in comprehension. He might find the plastics more interesting, but the point is, you could have built a Lensbaby at any point in the last three hundred years.<p>You can get even simpler than that, as my link notes. Poke a hole in a body cap with a hot needle, and you've made a pinhole "lens", which is thousand year old technology.[2]<p>1: <a href="http://www.dansdata.com/lensbaby.htm" rel="nofollow">http://www.dansdata.com/lensbaby.htm</a> for an excellent review. He's actually reviewing a Lensbaby 2, which uses a doublet instead of a single uncoated lens, to reduce chromatic aberration and flare, which is quite missing the point, I feel.<p>2: <a href="http://en.wikipedia.org/wiki/Camera_obscura" rel="nofollow">http://en.wikipedia.org/wiki/Camera_obscura</a>