With its new 200-megapixel Isocell HP2 image sensor, Samsung aims to give smartphone photographers the best of both worlds: high resolution and good image quality in challenging conditions.
HP2 is in mass production. Samsung hasn’t revealed a shipping date or confirmed which phone it will arrive with. However, the sensor is expected to power the main camera on the company’s flagship Galaxy S23 Ultra phone, which is likely to launch on February 1.
Image sensor designers face a trade-off. Increasing the resolution means that each pixel on the sensor is smaller, and smaller pixels can’t gather light as well. That means low-light shots are marred by speckles of noise. They lose detail in the shadow areas of the scene. And they suffer from spoiled highlights in bright areas like the sky.
However, the HP2 brings new techniques to counteract those problems and make the most of each photon of light, Samsung told CNET exclusively.
The South Korean electronics giant’s sensor can primarily collect light more efficiently, boosting high dynamic range (HDR) photos to better handle scenes with dark and bright elements, the company said. And when shooting with 200 megapixel resolution, Samsung uses AI technology to show the best details.
It’s not yet clear how well the sensor will perform in real-world testing. But it’s no surprise that Samsung is focusing on technology. Camera improvements are the main reason to upgrade phones, with better photos and videos more noticeable than slightly better processors, battery life and network technology.
“The full 200MP resolution especially shines when shooting concerts or outdoors, where there’s a lot of detail,” said Jun Seo Yim, executive vice president of Samsung Electronics’ sensor business. “It may not be the preferred setting for most consumers, but we definitely see the need for highly detailed images.”
Apple, Samsung’s main smartphone competitor, is also investing heavily in its cameras. Relatively large lens elements protrude from the back of the iPhone 14 Pro models to show off the camera’s performance, and Apple has upgraded its sensors for better high-resolution and low-light shooting.
Better pixel placement options
One of the headline techniques for enhancing smartphone photos is called pixel binning. With this, groups of physical pixels can be combined into larger virtual pixels that collect more light when it’s dim, trading resolution for lower noise and better color.
Samsung isn’t alone in using pixel placement. You will see it 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 a 2×2 pixel layout, which makes four physical pixels one virtual pixel. Samsung’s flagship Galaxy S22 phones from 2019 offer a 3×3 pixel setup that offers 108-megapixel photos in good light and 12-megapixel photos when it’s dark.
Samsung’s HP2 can take 200-megapixel photos in good conditions. When it’s blurrier, pixel binning groups the pixels into 2×2 slices for a 50-megapixel image. And when it gets darker still, Samsung’s 4×4 “Tetra2pixel” pieces snap a 12.5-megapixel photo.
Both levels of pixel placement were available on the 200-megapixel HP3 announced in 2022. However, the HP3 uses smaller pixels, which, while minimizing the camera’s bulk, don’t capture light very well in the first place. It also had the HP1 announced in 2021. But HP2 adds a few other tricks that HP1 lacks.
Pixel binning ups and downs
Pixel binning has several other advantages. Cameras can crop out the center of the image to zoom in on more distant objects. This is the main basis for efforts to give smartphones zoom capabilities like traditional camera lenses. Pixel binning also opens up new options for high-resolution 4K and 8K video.
Pixel binning has its downsides, however. Processing all those pixels takes a lot of battery power, and storing high-resolution photos takes up a lot of storage space. And high-resolution sensors, while good in principle, don’t achieve high image quality unless they’re paired with high-quality lenses.
“The full 200MP mode requires more RAM and power,” Yim said, which is why such high-resolution sensors can only be found in high-end smartphones.
One of the complications with the HP2 is color detection 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 pixel group captures only one of those colors. To fill in the necessary color detail in these 16-pixel groups, Samsung uses an artificial intelligence algorithm, the company said.
Samsung HP2 image quality improvements
The sensor has other tricks to enhance image quality, especially in high dynamic range scenes with both bright and dark detail. Here are some of them.
- A technology called Dual Voltage Transfer Gate (D-VTG) gives each pixel 33% better light-gathering ability, which should improve image quality in dim scenes and reduce diffuse white spots in bright skies.
- Samsung’s Dual Slope Gain (DSG) feature enhances HDR photos by digitizing exposure data for each pixel at two different scales to capture bright and dark data when shooting in 50-megapixel mode. The sensor’s abundance of pixels means that some pixel quads are optimized for bright light and others for lower light.
- A related feature, called Smart-ISO Pro, is a separate HDR technology that adapts to different scenes using different combinations of sensitivity settings to match the different frames used to create the HDR photo.
Another new feature of the HP2 is improved autofocus with a technology called Super QPD. Samsung says it can detect horizontal and vertical lines on 2×2 pixel groups, helping the camera lock onto details like horizons or tree trunks, even when it’s dim.
Each HP2 pixel is 0.6 microns or 6 millionths of a meter wide. That’s a shade narrower than the HP1’s 0.62 microns. For comparison, a human hair is approximately 75 microns. For combined 50-megapixel photos in a 2×2 array, the pixel width increases to 1.2 µm, and in 4×4 to 2.4 µm.
“We expect high-resolution image sensors to become a standard feature in future flagship smartphones,” Yim said. “Because of this, we believe it is important to continue our efforts, from sub-0.5 micron pixel processes to pixel performance and algorithms.”
Larger sizes collect light better. Samsung’s pixel sizes are pretty similar to the iPhone 14 Pro’s main camera sensor, which uses 2.44 micron pixels in 12-megapixel mode and 1.22 µm in 48-megapixel mode.
When it comes to video, the HP2 has plenty of options. It can shoot 8K videos at 30fps using the sensor in its 50-megapixel mode. It can shoot 4K video at 120fps, or if Smart-ISO is enabled, at 60fps. For 1080p video, the sensor will shoot at 480fps without autofocus and 240fps with autofocus.
