UPDATE: Huawei reached out with a statement to refute the original publication. The company claims there has been "significant technological collaboration" with Leica in the P9 and P9 Plus cameras' "optical design, imaging quality, image data processing, optimization, and the mechanical construction of the camera module, to the graphic user interface." It also notes that the devices "meet Leica’s highest imaging quality standards."
The Huawei P9 arrived alongside the P9 Plus at a special launch event in London a couple of weeks back to much excitement. Though a new flagship announcement from a renowned brand like Huawei is exciting enough, there was added intrigue due to the two rear-facing cameras, which, it was claimed, had been 'co-engineered' by Leica. A renowned German optics company, the Leica collab had much of the snap-happy tech world frothing at the mouth, particularly given what Carl Zeiss has done for Lumia devices over the past decade or so. As it transpires, Leica's input to the shooter's tech was superficial, and essentially, the logo is little more than a marketing ploy.
Not too long ago, firms capitalized on the naiveté of consumers by simply bumping up the resolution of each new smartphone snapper. Slowly but surely, the world learned that more megapixels doesn't always equate to a better performance, and thus, OEMs have since sought alternative ways to woo fans of high-end handsets.
Leica carries plenty of weight in the world of photography, so for Huawei to have the company's name emblazoned on its flagship handsets is quite a big deal. However, the P9 and P9 Plus' shooters are only 'certified by Leica', which, to put it simply, could mean little more than a Leica engineer testing out the device before saying 'yep'.
As noted by Übergizmo, Leica had no hand in the development or creation of the camera or its optics. In actuality, the components were made by a Chinese firm called Sunny Optical Technology. Apparently, the German company did help to create a 'picture quality algorithm', but aside from that, it looks like the Leica branding is mostly just that: branding.
This goes some way to explaining why, in our Huawei P9 review, we found the camera to be pretty good, but nothing particularly special.