Canon may be developing a Quad Pixel Autofocus sensor as the followup to its highly-regarding Dual Pixel AF. A newly-surfaced patent shows a sensor in which each pixel is split into not two, but four areas.
First launched in the 70D APS-C DSLR back in 2013, Dual Pixel AF splits each pixel on a sensor into two light-sensitive photodiodes. Since each half independently detects light through separate microlenses, the signals can be analyzed to glean focus information. The result of this is a phase-detection AF system that provides fast and accurate autofocus for both still photos and video.
Canon News discovered a Canon patent in Japan (2019041178) that describes the design of a quad pixel autofocus sensor.
“Right now Canon is using dual pixel autofocus sensors,” Canon News writes, “but if you ever tried to use an EOS R or an EOS M in landscape orientation to focus on a horizontal line you’ll quickly realize that the phase detect sensors just go in one direction, and have little sensitivity in the other 90 degrees offset direction.”
The new design would address this issue. The patent appears to describe a 20.7-megapixel sensor that contains a whopping 83 million focus detection points.
“The pixel size seems to be 4 micrometers, which would make that approximately 22mm on the width (5575×3725) or in other words an APS-C sized sensor,” Canon News says.
Canon may be looking into decreasing pixel density on sensors in favor of providing an even better autofocus system.
“Canon uses 180nm tech for its APS-C sensors that can incorporate copper wiring,” Canon Rumors writes. “This is probably fine for a 20mp image sensor. There would be a loss of efficiency splitting the pixels further and may lead to Canon dropping the pixel count on APS-C sensors.
“This would only matter if we actually do see QPAF sensors in the future.”