The Canon patent, number 2016-24391, describes a method by which Canon’s sensor would be able to detect autofocus errors and correct for them without needing to actually drive the AF motor — in other words, removing the need for the camera to hunt with its focus in and out.
The method, as described in the patent, would involve placing a polarizing filter between the lens and the imaging sensor. This filter would allow for the camera to detect how far it is front- or back-focused on its intended target, allowing for it to make adjustments without the need for refocusing multiple times, or hunting as we know it. How exactly this is achieved is not readily apparent from the patent, but the potential is definitely intriguing.
A key point to remember here, though, is that this is just a published patent, so there is no way of knowing if Canon has plans to ever introduce it in an official product. This patent in particular was actually filed in July 2014, but was only just published publicly this year. So don’t go getting too excited, but if you do, we don’t blame you. A world without AF hunting would be a glorious thing. Hint hint, Canon!
