With its new 200 megapixel Isocell HP2 image sensor, Samsung will try to give smartphone photographers the best of both worlds: high resolution and good image quality in difficult conditions.
The HP2 is in mass production. Samsung has neither announced its shipping date nor confirmed which phone it will arrive in. However, the sensor is expected to power the company’s main camera. flagship Galaxy S23 Ultra phone, likely to debut on February 1.
Image sensor designers make a tradeoff. The increase in resolution means that each pixel on the sensor is smaller, and the smaller pixels are not able to collect as much light. This means that shots taken in low light are clouded by speckles of noise. They lose detail in shadowy parts of a scene. And they suffer from lightning flashes in bright spaces like the sky.
The HP2, however, brings new methods to counter those problems and exploit every photon of light, Samsung revealed exclusively to CNET.
The South Korean electronics giant’s sensor can collect light more efficiently in the first place, enhancing high dynamic range (HDR) photos to better cope with scenes with dark and bright elements, the company said. And when shooting at the full resolution of 200 megapixels, Samsung uses AI technology to help render the finest details.
It’s not yet clear how well the sensor will do in real-world testing. But it is no surprise that Samsung focuses on technology. Camera improvements are a primary reason to upgrade phones, with better photos and videos more noticeable than marginally better processors, battery life and network technology.
“The full 200MP resolution shines especially when shooting at concerts or outdoors where there is a lot of detail to capture,” said JoonSeo Yim, executive vice president of Samsung Electronics’ sensor business. “It may not be the predominant setting for most consumers, but we definitely see the need for highly detailed images.”
Apple, Samsung’s main smartphone rival, is also investing heavily in its cameras. Comparatively large lens elements protrude from the back of the iPhone 14 Pro models to demonstrate camera performance, and Apple has upgraded its sensors for better high-resolution and low-light shooting.
Better pixel binning options
One of the headline techniques to improve smartphone photos is called pixel binning. With it, groups of physical pixels can be combined into larger virtual pixels that gather more light when it’s dark, trading resolution for lower noise and better color.
Samsung is not alone in using pixel binning. You will see it in the Apple iPhone 14 Pro, Google Pixel 7, Xiaomi 12T Pro and other phones, but the HP2 sensor is one of the most advanced. Apple and Google, for example, use 2×2 pixel binning which turns four physical pixels into one virtual pixel. The Samsung Galaxy S22 flagship phones have offered 3×3 pixel binning since 2019, offering 108-megapixel photos in good light and 12-megapixel photos when it’s dark.
Samsung’s HP2 can take 200 megapixel photos in good condition. When it’s darker, pixel binning groups the pixels into 2×2 pieces for a 50 megapixel image. And when dimmer still, Samsung’s 4×4 “Tetra2pixel” pieces take a 12.5 megapixel photo.
Both levels of pixel binning were available on the 200-megapixel HP3, announced in 2022. However, the HP3 uses smaller pixels which, while minimizing camera bulk, aren’t as good at capturing light in the first place. U HP1, announced in 2021, also had But the HP2 adds other tricks that the HP1 lacks.
Ups and downs of pixel binning
Pixel binning has some other advantages. Cameras can crop on the central part of the image to zoom in on more distant subjects. It is a key foundation for the effort it gives zoom capabilities to smartphones like traditional camera lenses. Pixel binning also opens up new options for high-resolution 4K and 8K video.
Pixel binning has disadvantages, however. It takes a lot of battery power to process all those pixels, and storing high-resolution photos eats up a lot of storage space. And high-resolution sensors, while nice in principle, don’t achieve superior image quality unless paired with high-quality lenses.
“The full 200MP mode requires more RAM and power,” said Yim, which is why such high-resolution sensors are only found on high-end smartphones.
One complication with the HP2 is calculating color when shooting 200 megapixel photos. Digital cameras capture red, green, or blue light for each pixel, but the Tetra2pixel design means that each 4×4 group of pixels captures only one of those colors. To help fill in the necessary color detail in those 16-pixel groups, Samsung uses an artificial intelligence algorithm, the company said.
Photography enthusiasts – a population likely to be very interested in the sensor’s high resolution – can shoot raw images at 200 megapixels, Samsung said. Raw images are larger, but offer higher image quality and better editing flexibility than conventional JPEG or HEIC photos.
Samsung HP2 image quality improvements
The sensor has other tricks to enhance image quality, especially with high dynamic range scenes with bright and dark details. Here are a few:
- The technology called Dual Voltage Transfer Gate (D-VTG) gives each pixel a 33% better ability to gather light, which should improve the quality of the image in dark scenes and cut the washed white parts in bright skies.
- Samsung’s Dual Slope Gain (DSG) feature enhances HDR photos by digitizing the exposure data of each pixel at two different scales to collect light and dark data when shooting in 50 megapixel mode. The abundant pixels on the sensor mean that some quartets of pixels are tuned for bright light and others for dimmer light.
- A related function called Smart-ISO Pro is a separate HDR technology that adapts to different scenes, using different combinations of sensitivity settings suitable for the different frames used to build the HDR photo.
Another new feature in the HP2 is improved autofocus with a technology called Super QPD. It can see both horizontal and vertical lines in groups of 2×2 pixels, helping the camera lock in on details like horizons or tree trunks even when it’s dark, Samsung said.
Each HP2 pixel is 0.6 microns, or 6 millionths of a meter, wide. That’s a shade narrower than the HP1’s 0.64 microns, which means the HP2 is a slightly smaller image sensor at 11.3×8.4mm. For comparison, a human hair is something like 75 microns. Combined in a 2×2 matrix for 50 megapixel photos, the pixel width increases to 1.2 microns, and in 4×4, to 2.4 microns.
“We expect high-resolution image sensors to become a standard feature in future flagship smartphones,” Yim said. “Because of that, we think it’s important to continue our efforts, from advanced pixel processes below 0.5 microns to pixel performance and algorithms.”
Larger sizes are better at gathering light. Samsung’s pixel sizes are quite similar to the iPhone 14 Pro’s main camera sensor, which uses 2.44 micron pixels in 12 megapixel mode and 1.22 micron in 48 megapixel mode.
When it comes to video, the HP2 has several options. It can shoot 8K video at 30 frames per second using the sensor in its 50 megapixel mode. It can shoot 4K video at 120fps, or, if Smart-ISO is engaged, at 60fps. For 1080p video, the sensor will shoot at 480fps without autofocus and 240fps with autofocus.
Correction, 2:48 pm: This story got the pixel size wrong on the Samsung Isocell HP1 image sensor. Each pixel is 0.64 microns.