Periscopes? RYYB sensors? There’s enough new camera tech packed into the Huawei P30 Pro that you might be baffled by the new terminology.
Mostly all you need to know is that the flagship smartphone’s camera is versatile, outdoing competitors in some key areas like zoom and nighttime shots. But Huawei’s technology could well spread farther across the industry, so it’s worth understanding what makes the phone’s four cameras tick.
Expect even more changes with smartphone photography from other players as new software and hardware arrives. Today’s phones have phenomenal cameras compared with models just a few years ago, but they still have a long way to catch up to dedicated cameras — the kinds with no phones attached, if you remember those.
There are many avenues of improvement. Google’s computational photography is impressive; Apple could get dramatically improved image sensor technology from its acquisition of InVisage; and merely having two main cameras is starting to look like skimping as phones sprout multiple cameras.
P30 Pro photo trick No. 1: periscope lens
The P30 Pro is designed to address a big shortcoming of phones compared with traditional cameras: weak zoom. Phones are wide-angle affairs — even the 2X zoom cameras on Apple iPhones are telephoto only by comparison with the main camera. So it’s hard to photograph a bird, a child dancing on the stage or soccer player running down the field.
The problem is that telephoto lenses are big because of optical physics, and nobody wants a camera bulge on a sleek smartphone.
The Chinese phone maker’s answer is to turn the camera sideways so its bulk is tucked away. A prism bounces light 90 degrees into the interior of the phone where there’s room for a longer optical pathway that ends in an 8-megapixel sensor. This periscope camera approach is what Oppo promised with its upcoming 5G-capable phone.
The result is a camera that can zoom in 5X compared with the main camera — the equivalent of 125mm in old-style 35mm-format camera terms. That doubles to 10X when combined with some digital zoom processing. It’s not going to match superzoom cameras or big telephoto lenses on DSLRs, but my colleague Andrew Hoyle calls the zoom ‘genuinely impressive.’
And for those interior architecture shots and nature panoramas, the P30 Pro comes with another separate camera with a 20-megapixel ultrawide lens.
P30 Pro photo trick No. 2: SuperSpectrum sensor
Smartphone camera technology moves fast enough that it’s surprising to realize one key component called the Bayer filter dates back to the 1970s. Huawei wants to change this basic aspect of digital photography.
Image sensors detect only the brightness of light. So to capture color, an array of tiny filters controls the light frequencies that reach each photosite on the sensor. When you take a typical digital photo today, raw sensor data for each pixel stores information for only one color — red, green or blue — the three colors human color vision detect. The Bayer filter pattern is a sort of checkerboard with two green pixels for every one blue and one red pixel, which is why you’ll sometimes see Bayer sensors described as RGGB.
The Huawei P30 Pro’s main 40-megapixel camera, though, substitutes yellow for green with a technology it calls SuperSpectrum. You’ll sometimes see this approach called RYYB.
Why bother? Because there’s more yellow light around, giving 40 percent boost and letting the camera work better in dim conditions. Huawei’s maximum ISO sensitivity setting is a whopping 409,600, up from ISO 102,400 in last year’s P20 Pro camera. Take those numbers with a grain of salt, but they do signal improved low-light performance.
Again, Huawei isn’t the only one to try breaking free of the Bayer history. Fujifilm’s X-Trans sensors capture red, green and blue but in a different pattern to try to improve overall results. Kodak has touted technology that swaps out a green pixel for a transparent pixel. And image sensor maker ON Semiconductor has technology called Clarity+ that uses two transparent pixels and doubles low-light performance.
Why have Bayer filters lasted?
Better low-light performance is a big problem for people taking pictures at restaurants and other dim locations, so SuperSpectrum solves a real problem. But there are downsides.
For one thing, color handling is different. Yellow is much closer to red on the color spectrum than green is, so reconstructing all three red, green and blue color values for each pixel requires heavier math. Huawei has earned respect for its cameras and likely didn’t embrace RYYB lightly, but the Bayer-pattern sensors are simpler and well understood in the industry.
Another complication: you shouldn’t expect to be able to shoot raw photos with the P30 Pro’s main camera — something that’s common with enthusiasts with higher-end cameras and increasingly beneficial on smartphones. That’s because you’ll need software like Adobe Lightroom to process the raw data into an ordinary image, and that process, called demosaicking, isn’t supported at least yet for the P30 Pro’s SuperSpectrum sensors.
‘Adobe can add direct support for any new non-Bayer mosaic filter array, but it takes significant time and effort,’ the company said in a statement. ‘On an easy-normal-hard difficulty scale for camera support, a new mosaic filter array counts as extra hard.’
P30 Pro photo trick No. 3: TOF sensor
The P30 Pro has a time-of-flight (TOF) sensor that might be new to you. Its purpose isn’t to take a photo but instead to augment other photos by gathering 3D scene data called a depth map.
Depth maps add a new dimension to photos — literally — which can be very useful. For example, a camera can figure out that it should expose a photo for a shadowed person in the foreground, not a bright landscape behind. Depth maps also help with AI tasks like recognizing faces and running augmented reality (AR) apps.
And most important, depth maps let you blur backgrounds to focus attention on the subject of a photo.
There are other photo features in the P30 Pro, too, including a better, AI-boosted night mode for very dark situations, silk water effects that simulate long exposures the way mobile apps like Spectre and Lightroom can; and ‘AI HDR+,’ which takes advantage of depth information to expose foregrounds and backgrounds properly.
Together, it’s one of the highest-profile examples of how crucial photography is to smartphones. Huawei pulled out all the stops for its new flagship phone. Just don’t expect this to be the last phone to advance the state of the art.
Huawei isn’t well known in the US — except perhaps for recent political troubles involving mobile network equipment it sells to carriers — but they’re a powerful force in phones.