Monday, February 27, 2012

Nokia 808 Phone Features 41MP (!) Sensor

Nokia announces 808 PureView smartphone featuring its PureView imaging technologies - a combination of high resolution sensor, Carl Zeiss optics and Nokia developed algorithms.

The Nokia 808 PureView features a large, high-resolution 41MP sensor with new pixel oversampling technology. At standard resolutions (2, 3, 5 and 8 megapixels) this means the ability to zoom without loss of clarity and capture seven pixels of information, condensing into one pixel for the sharpest images imaginable. At high-resolution (38MP maximum) it means the ability to capture an image, then zoom, reframe, crop and resize afterwards. The new camera phone is said to have a superior low-light performance.

The Nokia 808 PureView is also capable of full HD 1080p/30fps video recording and playback with 4X lossless zoom.

The sensor size is huge 1/1.2-inch, approximately 2.5 larger than the sensor used
in its predecessor, the 12MP Nokia N8. The pixel size is 1.4um.

The dedicated PureView page shows the phone with 41MP label on the camera and Youtube videos (Video 1, Video 2):






Nokia whitepaper reveals few more bits of information about the new sensor:

"So how is this possible?

The starting point is a super-high-resolution sensor. This has an active area of 7728 x 5368 pixels, totalling over 41Mpix. Depending on the aspect ratio you choose, it will use 7728 x 4354 pixels for 16:9 images/videos, or 7152 x 5368 pixels for 4:3 images/videos as is shown in Figure 1:"


"Pixel oversampling combines many pixels to create a single (super) pixel. When this happens, you keep virtually all the detail, but filter away visual noise from the image. The speckled, grainy look you tend to get in low-lighting conditions is greatly reduced. And in good light, visual noise is virtually non-existent. Which means the images you can take are more natural and beautiful than ever. They are purer, perhaps a more accurate representation of the original subject than has ever been achieved before."

"With the Nokia 808 PureView, you get effective maximum aperture throughout the zoom range. Whereas with optical zoom, less light tends to reach the sensor as the zoom increases. At maximum zoom, 5.4x more light reaches the Nokia PureView Pro sensor than a broadly equivalent optical-zoom digital camera (f/5.6 as opposed to f/2.4). And this means you get the benefit of faster shutter speeds."

The formal camera specs are:

The technology:
PureView Pro imaging specifications


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

The product:
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: 1.4um

Regarding the pixel size Nokia writes:

"People will inevitably home in on the number of pixels the Nokia 808 PureView packs, but they’re missing the point. The ‘big deal’ is how they’re used. At Nokia, our focus has always been capability and performance.

The main way to build smaller cameras over the years has been to reduce the pixel size. These have shrunk just over the past 6 years from 2.2 microns, to 1.75 microns, to 1.4 microns (which is where most compact digital cameras and smartphones are today). Some new products are on the way with 1.1 micron pixels. But here’s the problem. The smaller the pixel, the less photons each pixel is able to collect. Less photons, less image quality. There’s also more visual noise in images/videos, and various other knock on effects. In our experience, when new, smaller pixel size sensors are first released, they tend to be worse than the previous generation. While others jump in, banking on pixel numbers instead of performance, we prefer to skip early iterations.
"

Update: Nokia Conversations, the official Nokia blog shows Youtube video of Juha Alakarhu, the head of imaging technology group:



Nokia also offers sample unretouched pictures from the camera here.

AllThingsD shows internals of the new Nokia camera and talks about the camera development process which took 5 years.

Update #2: As written in comments, The Handheld Blog published a video interview with Damian Dinning, the member of Nokia camera team, where he says few words about the sensor:



Update #3: Venture Beat published another video interview with an engineer from Nokia camera team showing sample pictures and explaining 808 camera decisions:



Nokia Conversations compiled a page of 808 camera reactions from the internet media.

Eero Salmelin, Head of Imaging at Nokia, features at I3A site (just a coincidence?). Just two months ago Eero won I3A annual Leadership Award.

26 comments:

  1. Good morning ! First we got 36 M in the D800, now 41 M in a mobile phone ....

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  2. I like the idea of oversampling the image plane but seems a little over the top for a camera phone.

    We need to remember that the vast majority of images will be downsized for the web/facebook or will be printed at maybe A4 (max). While digital zoom and re-framing etc in post are useful they are covering for a lack of thought when the user presses the shutter. There is the argument that as cameras become ever more automated it forces the loss of knowledge from the user, thereby prompting more automation.

    The use of oversampling is a good one, reducing the noise of the 7:1 output pixel is a nice touch, probably will give a nice colour rendition too depending on the interpolation algorithm. It will be interesting to see low light images from the sensor.

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    Replies
    1. oh wow. All i can say is Good luck Facebook server =D

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  3. Seems to take pics of the future, too: http://cl.ly/EXtr

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    Replies
    1. it can happen if one did not set the date of the phone properly. not a big deal

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  4. This is the first cameraphone that will have fantastic non-interpolated digital zoom (just reads out a smaller portion of the sensor). Have you ever zoomed in with your phone? Gets blurry/noisy real fast. This camera has f/2.4 with 5 aspheres, a serious lens system.

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  5. I like the AllThingsD article's comment about how hard it is to make mechanical zoom. Take note, everyone developing or selling a mechanical zoom system. OEMs would rather build a absurdly expensive custom camera system instead of adopting mechanical zoom.

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  6. Does anyone have any idea who might be behind this 42Mpx sensor design?

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    Replies
    1. Would be interesting to know.

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    2. Damian Dinning (the head camera guy @ Nokia) said they approached partners Toshiba and Sony but they didnt have a sensor that Nokia wanted/needed

      so Nokia designed it and worked with "partners" to manufacture it you can find that interview on thehandheldblog or from the youtube video here http://www.youtube.com/watch?v=ZheH4PjEows

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    3. http://www.arnnet.com.au/article/416662/nokia_unveils_41-megapixel_imaging_sensor_technology

      This article seems to confirm that its made by Toshiba?

      Interesting to know the power consumption for the 38MP mode or even the 8M/5M modes scaled down from higher resolution?
      Any idea on the # of CSI-2 lanes?

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    4. The statement that the sensor was "developed with Toshiba and other Nokia partners" appears on many sites all other the Net. I'm still unable to find the reference to the source of this information.

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  7. Someone puts this http://www.cmosis.com/products/standard_products/chr70m in a mobile phone... that would be hilarious :D

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  8. Question I have is the max frame rate @ 42M resolution.

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    Replies
    1. Assuming 4 Lane MIPI it should be around 5-7 fps

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  9. And what about the IF BW and the recieving ISP, assuming it is a RAW sensor as is common in Nokias designs. I'm guessing some kind of sliced approach in the ISP with multiple passes, would those slice borders be visible in the images?

    Coming to the design & manufacture of the sensor, could it be ST with their Edinburgh team?

    /JS

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  10. The noise in the sample images that are @ISO50 is awful, and that's what you get from 1.4um pixels.
    41mpx is only a marketing gimmick, so that the user will get a better 'digital zoom'. Quality wise - nothing much.

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  11. I beg to disagree. The gradiations of the skies are not terrific, but that has little to do with the noise characteristics of the sensor itself. Pushing the images a lot did not show any noise issues, so I wonder where you saw this awful noise. Considering the level of details and low noise levels, it is hardly a marketing gimmick.

    (Unfortunately the phone doesn't seem to allow raw image output, so performance data of the sensor itself is not possible to get.)

    Also, it is the size of the sensor and the quality, not size of the pixels which are relevant to the noise in the output image.

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    Replies
    1. Could you elucidate on your last point?

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    2. @ The first anonymous: what has the size of the sensor to do with noise? So people like me working on lowering pixel noise has simple way out: just increase the chip area and "quality" and somehow magically the sensor noise comes down. Gosh, I lost my job :)

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  12. One of the figures Vladimir included indicates that even though there are north of 41 million pixels, the two operating modes are a 4:3 mode using 38.391 million pixels and a 16:9 mode using 33.647 million pixels. The specifications give lossless zoom figures of 3x for still images and 4x for full HD 1080p video. At 30 frames per second, the 16:9 mode would have something like 1 Gs/sec A/D throughput, which suggests to me that there's some immediate binning to get down to data rates that are easier to digest. Then you could get the lossless zoom by omitting some of the binning operations. It doesn't seem likely to me that the video would allow lossless zoom after capture. I would guess if the chip can handle 2 Mpixel at 30 fps, full-resolution stills would take a little more than half a second each.

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  13. Good device!! However, you cannot enjoy the clarity unless you have a screen to view the images of such a resolution. To me anything more than 12 MP is not going to be good unless, you are a professional(I mean real professional photographer, not some monkeys with DSLRs!!!). 12 MP is more than enough for a mobile - I would not recommend to go for a mobile with anything greater than 8 MP.

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    Replies
    1. The reason is the zoom! Also in the advertisement they say that they need high resolution for lossless zoom, or better, avoid mechanical zoom lens.

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    2. more megapixels = more flexibility for post processing. (easier cropping.) but it is obvious you do not know much about photography so stay happy with you 12mp phone camera

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    3. "more megapixels = more flexibility for post processing"
      Then buy the silly camera, not a mobile phone...

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  14. Does anyone know who actually manufactured to lens?

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