A camera lens, historically, can only focus on one thing at a time, just like the human eye. That could be a thing of the past, though, thanks to a breakthrough lens technology developed by researchers at Carnegie Mellon University (CMU) that can bring every part of a scene into sharp focus, capturing finer details across the entire image, no matter the distance.
Traditional lenses are limited to sharpening one focal plane (the distance between an object and your camera) at a time, blurring everything behind or in front of that object. That effect can bring a sense of depth to images, but seeing a full picture clearly typically requires you to combine multiple photographs that were shot at different focal lengths. This new “spatially-varying autofocus” system instead combines a mix of technologies that “let the camera decide which parts of the image should be sharp — essentially giving each pixel its own tiny, adjustable lens,” according to CMU associate professor Matthew O’Tool.
The researchers developed a “computational lens” that combines a Lohmann lens — two curved, cubic lenses that shift against each other to tune focus — with a phase-only spatial light modulator — a device that controls how light bends at each pixel — allowing the system to focus at different depths simultaneously. It also uses two autofocus methods: Contrast-Detection Autofocus (CDAF), which divides images into regions that independently maximize sharpness, and Phase-Detection Autofocus (PDAF), which detects whether something is in focus and which focal direction to adjust.
The experimental system “could fundamentally change how cameras see the world,” according to CMU professor Aswin Sankaranarayanan.
It isn’t available in any commercial camera you can actually buy, and it may be some time before options start appearing on the market, if ever. CMU researchers suggest that this tech could have broader applications beyond traditional photography, however, including improved efficiency in microscopes, creating lifelike depth perception for VR headsets, and helping autonomous vehicles to see their surroundings with “unprecedented clarity.”
