Types of active autofocus[]
I've been told on several occasions that some active-autofocus systems measure the time between emitting a light pulse and its return to the sensor. This violates no physical laws, but the precision required seems difficult to achieve in a modestly priced consumer product. Does anyone know for sure? William Sommerwerck 12:33, 26 January 2010 (EST)
I know I'm two years late, but yes it is. This system has been known for ages, see this patent: http://www.patents.com/us-5337116.html nothing special about it, the tech capable of such precision has been in cameras at least since the 1970's. Frankly, I think the description of active AF system on this page was pulled out of someone's ass. There are several IR active systems, from simple echo calculation to active/passive hybrid triangulation system (Canon), but I've never heard about a system described here. But the wording is so poor I might have misunderstood it. I'll come back later and try to fix it, though it'd be ince if someone more knowledgable would. 193.110.186.126 00:40, September 13, 2011 (UTC)