Home Nokia Nokia 808 PureView: The Technology Behind Pure Imaging and The Information to Learn

Nokia 808 PureView: The Technology Behind Pure Imaging and The Information to Learn

15 min read
1
nokia-808-pureview-camera

41 Megapixels sensor just inside a smartphone? Along with many others out there, we also were surprised when Nokia stated about its new camera phone “Nokia 808” codenamed “PureView” yesterday at MWC. No one could have guessed that it will be having 41MP camera sensor, though it was all known that Nokia is going to launch a successor to its own Nokia N8 having ideas of “may be 16MP or so”.

nokia-808-pureview-camera

After the big surprise Nokia has given at show, many started saying like “megapixels war is over” or a few said like “it’s just a marketing gimmick and putting 41MP camera in a phone doesn’t make it better camera”. It’s true that the 41MP factor in Nokia 808 really surprised and made many users thinking over if it really could do, with its 41MP camera, a better job?

On the other side of course, for Nokia fans, 41MP was a next benchmark putting the original Nokia N8 at number 2 in the top camera phone’s list.

“But! the thing is really not the quantity of megapixels at which a better camera can be identified. And also the thing is not to neglect the “way to use” behind that quantity of megapixels.”

Nokia has mentioned in the announcement that the combination – of 41 Megapixels, the high performance Carl Zeiss optics and Nokia’s brand new pixel-oversampling technology – isn’t about shooting pictures billboards sizes. Instead, it’s about creating amazing pictures at normal, manageable sizes. There’s a combination of benefits.

To explain the detail of 41MP and combination used in Nokia 808, for the consumers and industry experts, Nokia has published a whitepaper describing every bit of the technology used in smartphone. It does tell how Nokia 808 makes use of those 41 Megapixels to shoot amazing pictures.

nokia-808-pureview-41MP-sensor-diagram

38 or 34! not 41 megapixels

The thing to note, is that the sensor will not produce images of its full 41 Megapixels as it overflows the standard optical format area, hence a particular area at corners is not used as illustrated in above diagram. At the end two maximum resolutions are achieved by this 41MP Sensor which are

  1. Resolution of 38 megapixels (7152 x 5368) at 4:3 ratio of dimensions
  2. Resolution of 34 Megapixels (7728 x 4354) at 16:9 ratio of dimensions

Technically you can say that Nokia 808 PureView will produce images of 38 Megapixels at maximum. But again to remind you that it’s not the quantity of megapixels that produces the better picture. There are other elements in a camera that, in combination, generate a good picture.

1/1.2″ sensor size, Oversampling and Cropping:

Very first thing is of course is the size of sensor used in Nokia 808 that is 5 times larger than the standard 1/3.2″ used in other mobile phones, almost 3 times larger than most of the compact digital cameras and 2.5 times larger than the one used in its predecessor Nokia N8.

At normal (recommended) settings picture is shot on 8 Megapixels but of course it’s not the same quality of other 8MP camera phones. Instead Nokia 808 uses the technique of oversampling and reduces the size of pixels to fit 7 of total pixels into 1.

That is the point which actually differs Nokia 808 from other camera phones and in fact the dedicated compact cameras. Oversampling actually waves off the need of optical zoom and in fact “lossless” digital zoom can bring the same or even more quality in smaller space. Oversampling, where gives the noise-less quality at 5 Megapixels, magnifying-in will not have that much noise-less quality but it will maintain the exact 5 Megapixels quality while you have fully zoomed into 3x (max). This also can be understood as cropping into the center of the image to 1-in-1 pixel.

Additionally there is also a “Creative” shooting mode option to use shoot photos at full of 38 megapixels at 4:3 ratio or 34 megapixels at 16:9 ratio.

At some point AAS also has tried to answer a question if Nokia 808 is a successor to Nokia N8. Due to the “Optical Zoom” found in Nokia N93 and N93i, they said it to be the successor of it instead of Nokia N8 because it was started to be developed in parallel to Nokia N8.

Well at some extent it can be al right but to me Nokia 808 still will be a successor to Nokia N8. Simply according to the definition, Nokia 808 will take the place of Nokia N8 and not the Nokia N93 in terms of the best “Camera Phone”.

f/2.4 aperture and Faster Shutter speed

As already cleared with PureView, Nokia avoided the Optical Zoom and instead used digital zooming along with oversampling pixels and f/2.4 aperture which will give more advantage over optical zoom as claimed by Nokia. Well logically it’s true.

Compact cameras with optical zooms use smaller apertures when zooming, that leads the ISO sensitivity to be set at higher and shutter speeds at lower to avoid blur in moving or even stills. Opposing to all that, f/2.4 aperture used equipped in Nokia 808 won’t let you face that issue because there is no optical zoom. And due to having the digital zoom, the same light will be available to the sensor leaving the ISO sensitivity at lower and using the faster shutter speeds.

Autofocus and Oversampling in Videos

Most beautifully Nokia 808 uses the same technique while recording HD videos up to 1080p.

Video autofocus was an area that needed to be dramatically improved. Because of Nokia 808 PureView’s much larger image sensor (5x larger than rival smartphones) the optics give you a relatively shallow depth of field. What’s more, we’re also using oversampling techniques in video to achieve our holy grail of low visual noise with extremely high levels of detail.

What’s more important is that Nokia 808 is capable of using autofocus in all shooting modes

We made our autofocus system more precise, sensitive and controllable. You get continuous
autofocus in all shooting modes, but we’ve also provided easy access to an On/Off control. In Off mode, the lens is set to hyperfocal, making it easier to get acceptable focus across a wide range of subject distances while eliminating focus hunting. There’s also Touch Autofocus for video and still images. In Creative Shooting mode, we’ve gone even further. A long touch on the viewfinder will bring up a pop-up UI window, where you can select Automatic or Macro. Close-up focus is much improved in Macro, while Automatic does all the work for you.

Processing Power

The company also clarifies about the delay in bringing Nokia 808 PureView (whilst it’s no delay by any mean – there is no similar technology even after Nokia N8).The processing power is the main thing, with which Nokia excuses for the delay. While mentioning about it, it’s also clarified that unlike other manufacturers cropping off a section of the sensor to ease the processing load, Nokia 808 PureView has no limited field of view as well as it provides lossless zooming capability, which is output resolution dependent.

  • Full HD 1080p gives you 4x zoom.
  • For 720p HD video, you’re looking at 6x lossless zoom.
  • nHD (640×360) video, an amazing 12x zoom

Encoding is done at up to 25mbps in high profile H.264 format

Sample Pictures and Videos

There is set of pictures shot and videos recorded with Nokia 808 PureView, which you really will not want to miss out.

Click here to see more sample pictures and videos

PureView Pro imaging specifications

  • 41Mpix sensor with pixel oversampling
  • Lossless zoom: 3x for stills, 4x for full HD 1080p video
  • Carl Zeiss optics

Nokia 808 PureView lens and sensor specifications

  • Carl Zeiss Optics
  • Focal length: 8.02mm
  • 35mm equivalent focal length: 26mm, 16:9 | 28mm, 4:3
  • F-number: f/2.4
  • Focus range: 15cm – Infinity (throughout the zoom range)
  • Construction:
    • 5 elements, 1 group. All lens surfaces are aspherical
    • One high-index, low-dispersion glass mould lens
    • Mechanical shutter with neutral density filter
  • Optical format: 1/1.2”
  • Total number of pixels: 7728 x 5368
  • Pixel Size: 1.4 microns (1.4um)

f/2.4 aperture inside Nokia 808:

Nokia 808 PureView:

“Introducing Nokia 808 PureView” by Juha Alakarhu – the Head of Imaging Technologies at Nokia

External articles:

And here it is if you want to read the company’s issued whitepaper on the PureView Pro technology.
The experts at photography centric dpreview have also covered the giant 41MP Sensor in Nokia 808.
Joshua from CNET has also put his point of view on Nokia 808

 

Load More Related Articles
Load More By Khurram Ali
Load More In Nokia