PureView Phase 2, or how Nokia managed to surprise us with an 8MP camera module
"Oh, dear, just 8MP? How can they call this PureView?", was the question on everyone's mind when the camera resolution of the Nokia Lumia 920 was leaked and then confirmed today. Nokia's camera guru Damian Dinning was quick to counter on Twitter that "it's not the megapixels, but what you do with them", and advised patience.
Its engineers managed to build a tiny spring-based system called "floating lens" around the camera unit in the Lumia 920, that keeps it steady regardless of your shaky hands - the main reasons low-light shots with phones become blurry. This true optical image stabilization is purely hardware-based, hence it allows the shutter to stay open longer, and the sensor get more light on its surface without the risk of blurring the image in the meantime.
Today we know why - the 8.7MP sensor resolution is far from the 41MP one on the Nokia 808 PureView cameraphone, but it represents the first step in the PureView Phase 2 technology, as Nokia calls it. It is designed for mainstream smartphones, not enthusiast niche devices like the 808 PureView, hence the requirements for a smaller module that will fit in the body of today's anorexic smartphones, where design matters a great deal for successful sales.
PureView Phase 2 white paper confirms that while the 41MP sensor was developed with the maximum amount of detail and sharpness, as well as lossless zoom capabilities in mind - things that would make shutterbugs leave their DSLRs at home for imromptu shots.The
The 8.7MP PureView one has been built from the ground up with the thought to resolve the issue that plagues smartphone cameras the most, due to their smallish sensors - low-light performance. Nokia didn't achieve that by placing a huge sensor behind the Carl-Zeiss lens, like on the 808 PureView, that will capture more light, but rather went the other way around.
A pretty clever idea to get a 1/3" sensor, like the one in the Lumia 920, perform better in certain low-light photography scenarios then the huge 1/1.2" surface in the 808 PureView. And we all know that when there is enough light, all flagship smartphone cameras perform with decent results now.
The 1/3" sensor is no larger than in your basic point-and-shoot camera, but the floating optics mechanism make its footprint in the phone larger, hence the slightly chubbier physique of the Lumia 920 than what we are used to see in today's flagships. On the right you can see the raw specs of the new module, that Nokia is entirely an in-house endeavor, developed in conjunction with Carl Zeiss as its most challenging project to date.
Instead of trying to fix individual lens elements, like with other OIS solutions, the wholel module of the camera is wrapped in spring mechanisms. These floating optics therefore allow much greater precision, correcting for up to 500 movements per second! This is precisely what allows 8x longer shutter speeds, and ensures your pictures will get much less blurry when taking them with one hand, which we so often do with our phones, and your videos won't be shaky all over.
Then comes the LED flash - instead of going with Xenon, which has some downsides in a smartphone environment, Nokia says the recent developments in LED are leaps and bounds ahead of the advancements in Xenon, so the Lumia 920 uses the modern pulse LED for a flash. It is capable of firing an intense burst of light for a very short time, that essentially freezes a moving object. Not short to the extent Xenon does it, but much better than conventional LED flash, says Nokia. Furthermore, the LED module can serve as continuous light while filming video, and of course doubles up as a torch.
Last but not least, Microsoft has worked very closely with Nokia to interwove the Windows Phone 8 camera software exclusively for the PureView sensor in the Lumia 920. Not only is everything, such as autofocus, auto white balance and so on, tailor-made for the sensor, but Nokia has included its unique denoising algorithms that keep the footage looking natural in low-light conditions.
In the end, the real-life picture and video samples will be the ultimate judge if the Nokia Lumia 920 manages to perform better than the flagship Android and iOS devices in low-light scenarios, and if it does, Nokia will have achieved its product differentiation goal with Windows Phone, but also the ball will be in the others court to improve in their turn, and we can only be happy about that.
See a few shots with a prototype Lumia 920 in the slideshow below compared to an undisclosed "competitor's smartphone", as well as a promo video for the new "floating lens" OIS technology in the slideshow below, and tell us what you think.