Samsung has announced the details of the ISOCELL GN2, its second-generation 50MP smartphone image sensor that features 1.4μm pixels, improved autofocus capabilities, better HDR capture and more.
The 1/1.12″-type (11.4 x 8.6mm) GN2 slightly increases the pixel size to 1.4μm, up from 1.2μm in its GN1 predecessor. For low-light scenes, the sensor can use four-pixel-binning that should simulate the light-sensitivity of 2.8μm pixels, albeit at the cost of resolution. If you’re looking for higher resolution, the GN2 has a new 100MP mode that uses an on-chip re-mosaic algorithm that combines three 50MP frames in red, green and blue to create a single upscaled 100MP image.
One of the biggest improvements in the GN2 should be its autofocus performance. The original ISOCELL GN1 used Samsung’s Dual Pixel autofocus technology. Similar to Canon’s Dual Pixel Autofocus (DPAF) technology, Samsung’s version split each pixel vertically into two photodiodes, effectively turning every pixel on the sensor into a phase-detection autofocus point.
|An illustration showing the diagonally-split green pixels used in the ISOCELL GN2. Click to enlarge.|
Now, in the GN2, Samsung is taking the technology a step further with Dual Pixel Pro. Instead of each pixel being split vertically, Samsung has incorporated green pixels that are split diagonally. Doing this means the green pixels now have a degree of sensitivity to vertical displacement in addition to horizontal displacement, which should effectively turn the green pixels into little cross-type autofocus sensors. While not exactly the same, it should offer similar functionality to the quad-pixel autofocus technology OmniVision showed off in its new OV50A sensor.
The GN2 also features Samsung’s new Smart ISO Pro technology, a new HDR capture mode teased earlier this month in the above video. Smart ISO Pro builds upon the original dual-gain Smart ISO technology found in the GN1, which enabled the sensor to switch between high-gain and low-gain readouts depending on the amount of light in a scene. Now, instead of simply switching between the two gain modes depending on the scene, the GN2 can read alternate lines of its sensor at different gain levels: one for preserving detail in the shadows and one for preserving details in the highlights and merge the images together to create a single photo with maximum dynamic range.
Samsung has also implemented a new ‘staggered-HDR’ feature in the GN2, which ‘uses rolling shutters over the same pixel arrays to capture multiple frames in short, middle, and long exposures.’ Compared to previous real-time HDR capture modes, Samsung says the staggered-HDR capture mode consumes 24% less energy for improved battery life.
On the video front, Samsung has also enabled 1080p video capture at up to 480 frames per second (fps) and 4K at 120 fps. Samsung says the ISOCELL GN2 is currently in mass production but doesn’t elaborate on what smartphone manufacturers will be using this sensor.