Zooming in on Nokia PureView

BARCELONA, Spain – It all started with a few glasses of beer and a napkin in a hotel bar.

Back in 2007, Eero Salmelin and Juha Alakarhu (pictured above) were on a business trip in Tokyo. Both guys were working with camera phones at Nokia and struggling with the problem of using zoom in such devices. Picture quality was simply not good enough. A part of the problem was the physical size of the components: everything in a mobile phone camera had to be small, which effectively meant poor quality.

Or did everything have to be small? Juha and Eero suddenly hit on a raving mad idea: why not cram a 40-megapixel sensor into a mobile phone? Surely it wouldn’t even be possible… Or would it? What if you took a risk, and only used the very latest technology available?

The guys sketched the first concept of what would later be known as Nokia PureView on a paper napkin.

How did this happen?

Fast forward five years. It’s Mobile World Congress in Barcelona, and a dark horse has stolen the show. Tech blogs are raving about a 41-megapixel camera phone that takes amazingly sharp photos.

How did they do it?

“When it comes to mechanics in the Nokia 808 PureView, we went over all the approved limits,” laughs Juha.

“This was a tremendous engineering achievement by a big team of passionate and dedicated people.”

“When we started this project in 2007, we kept it very secret. The imaging experts at Nokia and in our partner companies did an incredible job. None of us were willing to give in when facing this incredible challenge.”

“We made dozens of optical designs trying to build the sensor, tried many different options for the algorithms, and worked intensively with our partners on the sensor design.”

“We weren’t sure what kind of risks were involved, so we started concepting the technology for one device only. The device itself wasn’t actually relevant for us: we were more interested in the technology as a prototype.”

The guys finished their first camera module without a mobile phone and took the first pictures in early 2009.

“We compared the photos to those taken with a reference camera, and our photos were better. We immediately thought there must be something wrong with the camera, so we tried another one, and the same thing happened again.”

“The optics in Nokia PureView provides amazing sharpness. Few people will believe how sharp it is until they see the pictures. There is an old myth in mobile imaging that small lenses can’t produce good quality images. This is simply not true, since the performance depends on design, materials and the precision used in the manufacturing.”

PureView technology in a nutshell

So what did Juha, Eero and their team actually come up with? Let’s have a closer look at PureView.

At the heart of the Nokia 808 PureView sits a massive, 41-megapixel sensor with a 1/1.2” optical format. And it’s not just any old sensor. It has more capacity to collect light than any other camera sensor in the mobile market. But this alone is not enough. In order to read information from the sensor while you’re shooting video, you need a lot of processing power.

The physical zoom structure in Nokia PureView is actually a lot simpler than in many other camera phones. This enabled other innovations and led to the concept known as oversampling.

“We didn’t want to cheat by upscaling the photos,” says Juha. “You need to manufacture the lenses and the camera module extremely carefully. The sharpness and tolerance need to be on a completely new level.”

“We were very stubborn with the design and not willing to compromise. The biggest challenge we had with the optical design was to make it small enough, and we must have tried dozens of different designs. Every time the design got a little bit better, and finally it reached the level we desired.”

“After we were ready with the camera technology, we integrated the processor chip to make sure we had a multimedia-optimized device that was able to record high-quality video.”

“The Xenon flash in Nokia 808 PureView was specifically made for this device. The mobile phone is built around the camera and the Xenon flash.”

Isn’t that all a bit complicated?

“On the contrary,” says Juha. “The technology is not at all difficult for end users. Good cameras let you take good photos quickly and easily. That’s all you need to know.”

Not a step, but a breakthrough

It would be an understatement to say feedback for the PureView technology has been positive.

“People seem to realize this is not a step, it’s a breakthrough. We have changed the way cameras are built. Everyone has left our demos with a big smile on their face,” Juha says.

“I love seeing people’s reactions when they use the phone and see the photos. Now we have a little bit of time to work on the device before it starts selling, and this sets the bar even higher!”

When you do something crazy, the difficult gets easy

Juha and Eero have had a keen interest in photography ever since they were little boys. Eero’s dad was a professional photographer, and they used to have a camera laboratory at their house when Eero was small. His dad also owned a photography shop in Tampere, and Eero used to help there in his spare time. “I sold my first camera when I was 7.”

Later in life, Eero went to study electronics at the University of Technology in Tampere, and wrote his thesis on the topic of designing camera systems for mobile phones.

Eero and Juha were also involved in the making of Nokia’s previous imaging superhero, the Nokia N8, which taught them many things about building large sensors.

“With PureView, we were always trying to do something utterly crazy. After that, it was easy to do something that was only ‘difficult’, like the N8.”

They love problems!

So what’s it like to innovate at Nokia?

“Nokia has always given people the opportunity to innovate. What’s different nowadays is productization. We’re a lot better and faster in bringing the innovations into actual products,” thinks Eero.

In the last decade, Nokia has become the world’s largest camera manufacturer. Like a true engineer, Eero has made his own calculations: “If you line up all the camera components Nokia has ever manufactured, it takes you all the way from Tampere to Tokyo and quite a long way back. Every single one of those components has taught us something.”

Juha concludes: “Every component brings you new problems, and when you solve those problems you learn something new. We love problems!”