In recent times, Samsung and Motorola have been prepping 200-megapixel sensors (phones) and rumors about whether the next generation of iPhones will have 48-megapixel sensors have sparked a lot of discussion. It’s time to talk about an old topic: what the heck is going on with the high pixel mode on the phone.
First of all, the high pixel count on the phone may be output by overlaying multiple frames. This is very similar to the “shake” on a camera. The difference is that the phone relies on the shake of the handheld shot itself, while the camera is more finely shifted through the sensor displacement to achieve a finer displacement.
From 2014 to 2015, almost all domestic brands of camera phones are equipped with similar technology, such as the OPPO Find 7, which uses a 13-megapixel camera to take 50-megapixel photos, and the Jinli E8, which uses a 24-megapixel camera to take 120-megapixel photos.
▲ OPPO’s official Weibo promotion of Find 7 high pixel mode.
▲ High-pixel mode of the Golden E8 (intercepted from the Golden E8 launch video by Youku Technology)
Then, since the Huawei P20 Pro in March 2018. 48MP, 50MP, 64MP, 108MP …… These sensors do have tens or even hundreds of millions of pixels (photodiodes to be precise).
Most of these sensors are Quad-Bayer (some are 9 or 16 Bayer) and work most of the time with a combined output of near-neighbor pixels.
Most of the photos are taken at 10-16 megapixels for everyday use; when high pixel mode is enabled, the high pixel output is achieved through a combination of hardware and software.
▲ Common Bayer structure
▲The physical state of quadruple Bayer structure (left), and ordinary Bayer structure simulated by circuit (right)
48 megapixels, 12 megapixels in four-in-one
50 megapixels, 12.5 million in 4-in-1
64 megapixels, 16 million in four
108 million pixels, 27 million in quadrature, 12 million in 9
Quad Bayer is not new: the front camera of Apple’s iPhone 6 series, released in 2014, is a Quad Bayer structure. Nor is quadruple Bayer exclusive to mobile devices: the Nikon D1 in 1999, GH5S in 2018, Sony 7SM3 in 2020, and this year’s OZONE OM-1, all use sensors with quadruple Bayer or similar structures.
Compared to the regular Bayer structure, quad-Bayer can develop better-focusing performance and HDR high dynamic shooting capability, in addition to the publicity gimmick.
▲ The teardown shows that the Sony 7SM3 has a quad-bayer sensor structure.
The sensor of the ▲Ozine OM-1 uses a quad split photodiode, very similar to the quad Bayer sensor of the 2 x 2 OCL structure (only without the high pixel output mode).
Finally, despite the high pixel sensor, the practice of composing high pixels from multiple frames has been retained to this day.
On the one hand, it improves the image quality of secondary shots such as portraits, telephoto, etc. (the secondary shots are usually still with normal Bayer sensors).
On the other hand, multi-frame composite high pixel image quality is not necessarily worse than direct sensor high pixel output, but on the contrary, the experience may be better (enabling sensor high pixel output mode first tends to limit shooting capabilities and reduce processing speed).
