What is Phase Detection Autofocus?
To understand how Dual Pixel Pro works, it is important to first understand its foundational technology, Phase Detection Autofocus (PDAF).
Just like humans use their two eyes to focus, PDAF works by comparing the phase differences in images generated by left-looking and right-looking pixels, which allows the camera to calculate the focus distance, or the place where the two phases align.
Conventional phase detection systems use special, dedicated autofocus pixels embedded throughout the sensor, typically making up just a small portion of the total pixels. To create the left-looking and right-looking images for comparison, half of each pixel is blocked with metal so that they pick up light from just one side of the lens. Using a larger number of these dedicated autofocus pixels can make phase detection faster, but also can reduce the the amount of light captured, resulting in loss of image quality. That is where Dual Pixel technology takes autofocus to the next level.
Leveraging every pixel with Dual Pixel autofocus
With Samsung’s Dual Pixel technology, every pixel on the sensor is used for phase detection, while simultaneously receiving color information, greatly improving both the speed and accuracy of autofocus compared to conventional systems.
Each pixel on a Dual Pixel sensor contains two photodiodes, one left-looking, one right-looking. When capturing a scene, the phases from each pair of photodiodes is compared to achieve autofocus in just milliseconds. Since every pixel in the sensor is being used for both autofocus and color values, the sensor can achieve snappy autofocus without losing image quality.
Dual Pixel Pro delivers next-gen autofocus
Dual Pixel Pro takes autofocus to a new level. It uses green pixels that divide photodiodes with diagonal structure. These diagonally-split pixels compare the phase differences between the top and bottom of the pixel in addition to phase differences in the left and right sides.
As a result, Dual Pixel Pro delivers fast and accurate autofocus even under difficult conditions, such as low-lighting or fast-moving subjects. It also addresses certain limitations of Dual Pixel technology, which struggles to differentiate between the left and right sides of patterns such as parallel horizontal stripes. The addition of top and bottom phase detection means your camera can better distinguish these patterns, making it capable of quickly grabbing focus even when your subject is wearing a patterned shirt with horizontal lines.
From the glance of a loved-one, to an awe-inspiring firework display, our most precious memories are often fleeting. ISOCELL image sensors armed with the Dual Pixel Pro autofocus system ensure your favorite moments will never pass you by again.