Photographer Adrian Onsen wanted to use the AI Servo autofocus mode on his Canon 40D in low-light situations, but found that the AF assist beam is only emitted once until focus is achieved rather than every time the camera needs to refocus. He then purchased a laser pointer from a dollar store, disassembled it to obtain a defocused beam of light, and attached it to the top of his camera. The hacked-together AF assist tool ended up working pretty well — Onsen was able to shoot sharper photos at a dance club without anyone noticing the extra light. To learn more check out his in-depth writeup here.

AF Assist tool (via Hack a Day)