With its new 200-megapixel Isocell HP2 image sensor, Samsung will try to offer 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. Still, the sensor is expected to power the main camera of the company’s flagship Galaxy S23 Ultra phone, which is slated to debut on February 1.
Image sensor designers face a trade-off. The increase in resolution means that each sensor pixel is smaller, and smaller pixels cannot catch light either. This means that photos taken in low light are marred by specks of noise. They lose detail in shaded parts of a scene. And they suffer from blown highlights in bright areas like the sky.
The HP2, however, brings new ways to counter these issues and make the most of every photon of light, Samsung exclusively revealed to CNET.
The South Korean electronics giant’s sensor can collect light more efficiently in the first place, improving high dynamic range (HDR) photos to better cope with scenes with dark and bright elements, the company said. And when shooting at full 200-megapixel resolution, Samsung uses AI technology to help render the finest 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 a big reason to upgrade phones, with better photos and more viewable video than slightly better processors, battery life and networking technology.
“The 200MP full resolution shines especially when shooting at concerts or outdoors where there are lots of details to capture,” said JoonSeo Yim, Executive Vice President of Sensor Business at Samsung Electronics. . “It may not be the predominant setting for most consumers, but we clearly see the need for very 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 camera performance, and Apple has upgraded its sensors for better high-res and low-light shooting. .
Better pixel grouping options
One of the main techniques for improving smartphone photos is called pixel binning. With it, groups of physical pixels can be combined into larger virtual pixels that gather more light when low, trading resolution for lower noise and better color.
Samsung is not alone in using pixel binning. You will see it in the, , 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. Samsung’s Galaxy S22 flagship phones have offered 3×3 pixel grouping since 2019, delivering 108-megapixel photos in good light and 12-megapixel photos when dark.
Samsung’s HP2 can take 200 megapixel photos in good conditions. When lower, pixel binning groups pixels into 2×2 chunks for a 50 megapixel image. And when even weaker, Samsung’s “Tetra2pixel” 4×4 chips take a 12.5-megapixel shot.
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 clutter, aren’t as good at capturing light first. The HP1, announced in 2021, had it too. But the HP2 adds a few other tricks that the HP1 lacks.
The highs and lows of pixel clustering
Grouping pixels has other advantages. Cameras can crop the central part of the image to zoom in on subjects further away. It’s a key part of the effort to give smartphones zoom capabilities like traditional camera lenses. Pixel binning also opens up new options for high resolution 4K and 8K video.
Pixel grouping has drawbacks, however. It takes a lot of battery to process all those pixels, and storing high resolution photos consumes a lot of storage space. And high-resolution sensors, while nice in principle, don’t achieve optimal image quality unless paired with high-quality lenses.
“The full 200MP mode requires more RAM and power,” Yim said, which is why such high-resolution sensors are only found on high-end smartphones.
A complication with the HP2 is determining color when shooting 200-megapixel photos. Digital cameras capture red, green, or blue light for each pixel, but the Tetra2pixel design means that each group of 4×4 pixels captures only one of these colors. To help fill in the necessary color detail in these 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 better image quality and editing flexibility than conventional JPEG or HEIC photos.
Samsung HP2 image quality improvements
The sensor has other tricks to improve image quality, especially with high dynamic range scenes with light and dark detail. Here are a few:
- A technology called Dual Voltage Transfer Gate (D-VTG) gives each pixel a 33% better ability to gather light, which should improve image quality in dark scenes and reduce washed-out white spots in skies. luminous.
- Samsung’s Dual Slope Gain (DSG) feature enhances HDR photos by scanning each pixel’s exposure data at two different scales to collect light and dark data when shooting in 50-megapixel mode. Abundant pixels on the sensor mean that some quartets of pixels are tuned for bright light and others for dimmer light.
- A related feature called Smart-ISO Pro is a separate HDR technology that adapts to different scenes, using different combinations of sensitivity settings appropriate for the different frames used to create the HDR photo.
Another new feature of the HP2 is improved autofocus with a technology called Super QPD. It can spot horizontal and vertical lines across groups of 2×2 pixels, helping the camera lock onto 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, meaning the HP2 is a slightly smaller image sensor at 11.3 x 8.4mm. For comparison, a human hair is about 75 microns in diameter. Combined in a 2×2 array 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 of future flagship smartphones,” Yim said. “For this reason, we believe it is important to continue our efforts, from advanced sub-0.5 micron pixel processes to pixel performance and algorithms.”
Larger sizes are better for 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 pixels in 48-megapixel mode.
When it comes to video, the HP2 has plenty of options. It can record 8K video at 30 frames per second using the sensor in its 50-megapixel mode. It can record 4K video at 120 fps or, if Smart-ISO is enabled, 60 fps. For 1080p video, the sensor will shoot at 480fps without autofocus and 240fps with autofocus.
Corrigendum, 2:48 p.m.: This story has distorted the pixel size on the Samsung Isocell HP1 image sensor. Each pixel is 0.64 microns in diameter.