We live in a glorious age of dual-camera smartphones. Huawei uses a color sensor plus a monochrome sensor to enhance detail and contrast. LG has a standard angle camera plus an ultra-wide-angle one. Apple uses a pair of cameras to offer a 2x optical zoom.
Oppo is jumping into the dual camera age with their own take at MWC 2017: a two-sensor system that combines a standard angle camera with a telephoto zoom, but taking it all the way to 3x optical zoom with a system that uses a prism in a periscope arrangement. At first that might seem similar to the original ASUS ZenFone Zoom, and in a way it is, but for moving between the two zoom settings (and beyond), Oppo's opted for digitally melding information from the two sensors instead of ASUS's mechanical zoom that actually moved lenses inside the phone.
Turning the telephoto camera sensor so that it's pointing across the back of the phone and through a prism to see out gave Oppo more space to construct their lenses. This arrangement both reduces the intrinsic engineering challenges and cost challenges of having to miniaturize components and use expensive high-index lenses.
The downside is in size — the periscope arrangement takes up precious horizontal space to array its lenses and is 5.7mm thick. It's small, yes, but space in smartphones is becoming increasingly precious. Oppo's demonstration device (not a production bit of hardware by any means) sported an enormous top bezel to give the camera module space.
While the camera module itself is capable of 3x optical zoom, Oppo's touting this as a "lossless" 5x camera. They're doing some fancy image merging trickery, using data from both cameras to add detail to an otherwise digitally zoomed image. It's not that different from what Huawei is doing with the P10, where data from the dual cameras is combined to improve detail and contrast. While we can't yet verify the claims of "lossless" digital zoom, my brief time with the camera was encouraging. Oppo's demo devices actually zoomed to 10x digital with a surprising amount of detail and steadiness. And, yes, the demo software here is a blatant knock-off of Apple's camera app; hopefully the production hardware will come with different software.
Oppo's being tight-lipped about when we should expect their first phone using this tech, but we wouldn't be surprised if it comes later this year with a big focus on photography.