James Brown's "Animated Bokeh" Lens Adapter Puts Doom in the Highlights of Your Videos
LCD acting as a programmable iris provides the ability to force bokeh into any shape at all, up to and including animations.
Maker James Brown has taken a break from building volumetric 3D displays to create something different: a lens adapter that offers "animated bokeh" — up to and including, naturally, being able to display a game of Doom.
"Animated Bokeh has been on my whiteboard for a long time, and this is the result," Brown writes of the project, which turns a reflective LCD display with the reflective layer removed into a programmable digital iris for a interchangeable-lens camera. "I thought it would just be for cheesy novelty effects, but it also does lightfield manipulation that was cooler than I expected. I made a deliberate decision not to put Bad Apple or Doom on this, YouTube commenters be damned. But I'm going to put Doom on it, aren't I?"
"Bokeh" refers to the aesthetic quality of blurred portions of a photograph, created using a lens with a wide aperture. In highlights, the bokeh presents as an echo of the shape of the iris used in the lens: a circular iris will give circular blobs, a hexagonal iris will give hexagonal blobs. But what if you weren't limited to the shapes you can make from a mechanical iris?
That's the idea behind Brown's "animated bokeh" lens adapter. Built using a monochrome LCD panel, upcycled from old Nokia phones and with the reflective layer removed, linked to a Raspberry Pi RP2040 microcontroller and housed on a custom circuit board, the adapter blocks light in the shape of the user's choice — and can adjust it in real-time. Initial demonstrations for the project included "scanning" the light-blocking section across the screen, blocking and revealing light in patterns including half-and-half and four-quarters, and forcing the aperture into unusual shapes including spinning cogs and hazard warning signs.
While Brown's initial video stopped short of using the digital iris to play id Software's seminal first-person shooter Doom — something he's previously put on LEGO bricks and volumetric 3D displays — that didn't last long: a more recent update showcases the game being displayed on the LCD, viewable with a little squinting in the video's highlights.
More information is available in Brown's Mastodon thread, and in the video on his YouTube channel and embedded above; firmware source code and a simulator have been released on GitHub under an unspecified open-source license, with hardware design files to follow.