A few years ago, I found myself getting very interested in bokeh. Specifically, how the aperture shape in an otherwise well-corrected lens will give shape and structure to the blur field in an image.
(This was long before LensBabies came along.)
So I decided to create a lens mount that would let me drop in different aperture plates. Since most 35mm lenses are monolithic (breaking them open to change the aperture would be a big project), I cut a large format mount and rented some 4x5 optics. In place of the shutter (my 35mm camera has a focal plane shutter), I milled a slot for aperture plates.
Here are some samples of the result. I liked the more abstract versions from our test shoot, but the blur fields would easily make an interesting, weighty background for traditional cinematography, too.
Also, this could theoretically be done in software if you have a light-field image; coarsely, this can be done with Lytro's camera system, though this is one area where analog has higher resolution than digital at the moment.
