The Inside Story of Nokia’s 41-Megapixel Camera Phone: Five Years in the Making

If it were easy to put a decent zoom lens in a camera phone, Nokia might never have come up with its biggest breakthrough in imaging in years.

The technology in the 808 PureView phone introduced on Monday was the result of Nokia engineers struggling over the fact that optically zoomed lenses just don’t work well in tiny spaces like phones.

“We had been working for a long time [on] optical zooms and had learned the hard way how difficult it is to achieve good performance in smartphones,” Nokia head of imaging technologies Juha Alakarhu said in an interview last week. “Their structure is very complex and hard to manufacture.”

Plus, Alakarhu says, when zoomed in, such lenses let very little light in, meaning they don’t do well at night and suffer from a lack of sharpness.

Quite late one night, Alakarhu, Eero Salmelin and other colleagues were struck by another method. If a big enough sensor could be fitted into the phone, the camera could just zoom digitally and throw away the unneeded pixels.

“We were aware that it is possible to do zooming by very high resolution image sensor, but the idea of putting such a large and high resolution image sensor into a smartphone felt completely crazy,” Alakarhu said. “That was five years ago, and I guess it still feels like that.”

That said, Nokia has done it with the 808 PureView — or Hyperion, as it was code-named during development.

As Alakarhu and colleagues showed AllThingsD the camera technology last week, they were practically bursting at the seams. After all, they had been working on the technology in secret for the last five years.

Part of the challenge now will be explaining to the consumer why anyone needs that many megapixels.

One of the key advantages is it lets you zoom in three or four times in either photos or video and still have a sharp image. The picture of the camera, here, for example, is taken from the same wide shot of the camera and its sensors. In videos, the technology allows one to zoom in close while still maintaining an HD resolution.

Another plus is that the camera uses so-called “oversampling” to shrink the image while still making use of the information in the large number of pixels. Nokia said it can create a better five-megapixel image by using the data in the seven extra pixels to inform which single pixel it uses.

To illustrate the imaging quality, Nokia’s development team has quietly been traveling the globe and taking pictures at the full resolution of the camera. From the shots, the team has created massive prints rivaling those from professional cameras.

Alakarhu was in Las Vegas at the Consumer Electronics Show in January and wanted to get a few shots. But he was in a city filled with reporters and competitors.

To provide some cover, Alakarhu wrapped the phone in a thick rubber case to mask its design. Meanwhile, he tried to keep the phone literally close to his vest, lest anyone look too closely at the screen and notice things like a 41-megapixel resolution.

“I guess I felt a little bit like James Bond with a very special new gadget in a secret mission,” Alakarhu said. “It was fun, of course, even though I had to be very careful.”

One of the areas where Nokia is bound to be criticized — especially in North America — is the fact that it is bringing the camera technology first to its bound-for-extinction Symbian platform rather than to Windows Phone, which is its future. Nokia doesn’t even sell Symbian phones in the United States any more.

Developing the 808 for Symbian was necessary for a few reasons. First, as mentioned, Nokia has been working on this technology for five years and only gotten to know Windows Phone over the past year. Also, because it controls Symbian, it can craft the camera app and operating system fully to its liking.

That said, Nokia is promising the technology will eventually make its way to Windows Phone as well. It is not, however, giving a time frame.

In an interview, Nokia smartphone unit head Jo Harlow declined to say if the PureView technology would show up in Windows Phones this year, but said she is not worried about any technical hurdles involved in making the move.

“I’m not at all concerned about work that needs to be done to bring it to Windows Phone,” Harlow said.

For his part, Windows Phone head Terry Myerson said he is looking forward to the day when his wife stops carrying a high-end digital camera and uses a PureView-equipped Windows Phone instead.

Here’s a picture of part of the 808 team, also taken with the 808.