A patent recently filed by Olympus presents an interesting way of bringing 3D photography to their ILC cameras — by adding a second lens to the hotshoe. As you can see from the patent illustrations above, it would sit in the camera's hotshoe mount, and provide a second lens for stereoscopic shooting. Sounds intriguing, but doesn't take much to envision some of the problems it might have. For one, you'd be stuck shooting portrait orientation, or else the parallax effect will be vertical instead of horizontal. The other obvious difficulty would be the difference between the two lenses. Would this rig work with any lens on the main mount? Or only a specific one? What if the two lenses have different focal lengths and apertures? How is the second lens controlled? Is there a servo to automatically choose the correct angle it should be facing? Does it have its own sensor? As is so often the case, the devil is in the details.