By : Steve Chippy Paine

“What?” “Why?” These are the two words I heard the most in conversations about the Nokia 808 Pure View at MWC last week.  The same words could be muttered by millions of potential customers too. Here’s why the Nokia 808 Pure View deserves serious attention from everyone in the mobile phone and mobile camera space and why the 41MP number really means more than just marketing.

You might know me as the guy that still carries a Nokia phone. I’ve used the Nokia N82 and now the N8 for thousands of images of my family and friends and for thousands of images from events around the world over the last 4 years. I bought the N82 but Nokia gave the N8 to me as a test device in 2010. I’m still reporting on it, and locked into it, today. There’s nothing in the smartphone arena that beats it for stunning daylight photography and clear flash photography and nothing that beats it for camera connectivity. HSPA, Wi-Fi and 3G with connectivity to my favourite sharing sites. What more could you want from a camera?

More pixels?  How about 41 million? Welcome to the Nokia 808 Pure View

“What?” “Why?”

From a photography perspective, think of the 808 as an array of cameras. Close in technique to HDR photography (and probably large array telescopes) where multiple images are processed together to increase dynamic range, reduce noise or increase sensitivity, the Nokia 808 can produce 8 X 5MP photographs in one go, all from different sensor pixels, that are then processed together to reduce noise and increase effective light sensitivity. Rather than one huge image, you get a processed 5MP image (or 3MP or 8MP depending on settings) that should set new standards for ‘pure’ photographs from any camera.

And there’s more.

You also get, as seen on the Nokia N8 in video mode, lossless zoom. Actually it’s not completely lossless but as you zoom and crop the image, the camera starts to use more of the pixels as individual pixels and not part of a ‘super pixel.’ The result is that at full zoom you still get a 3, 5 or 8MP image that has been cropped from the full 41MP sensor. There’s another advantage associated with this digital zoom too though. As you zoom, you don’t have to close the aperture as you do on most optical zoom lenses. The result is F2.4 all through the zoom. That’s worth a good around 5 F-stops as the end of the zoom range. (For much easier low-light zoom photography.)

There’s more too. Check out the white-paper here (PDF) which talks about less diffraction, low distortion, no vignetting, noise-free zoom, eliminating Bayer pattern problems and the long focal length of the lens which will reduce the depth of field for good bokeh effects. I’ve read it at least 4 times now!

I’ve also spoken to  Juha Alakarhu and Damian Dinning – two of the senior engineers responsible for this technology. Although it’s not mentioned in much detail in the white paper, there’s a significant advantage in light sensitivity to be gained from pixel oversampling. I questioned the degree of advantage and Juha tells me that the increase in effective light sensitivity is nearly linear to the increase in pixels use in the super-pixel. At 5MP you could be seeing 8X better light sensitivity. To test that I took a few images with the Nokia 808 and also with my Nokia N8.

Nokia 808 8MP Nokia N8 12mp

The 808 image is on the left. It’s an 8MP image. The image on the right is from the N8 and it’s a 12MP image. Click through for full versions and EXIF data at Flickr but let me summarise here. Firstly, you’ve got a much brighter image there with the 808. I estimate 1/2 f-stop difference although this is being achieved with a bigger aperture at the same shutter speed which indicates to me that the effective sensitivity of the 12MP 1.7micron N8 is similar to the 8MP super pixel (estimated 2×2 pixels of 1.4 micron.)

Inspecting a crop is probably not the best idea here as the two photo’s were taken hand-held.

808 crop N8 crop

On close inspection the 808 image does seem to have the less noise though which would allow the 808 to choose a higher ISO for the same noise as on the N8 – effectively an increase in sensitivity for the same noise levels as the N8. At 5MP, the 808 is likely to be more sensitive,

In a second image I took at full resolution with the 808 and the N8. While the low-light hand-held images weren’t sharp enough to compare quality, I was able to take a look at the EXIF data and it shows the 808 was less sensitive than the N8. The 808 was able to use a faster shutter speed although this was only due to the F2.4 aperture compared to the F2.8 on the N8. Analysis of noise levels showed an advantage to the N8. This is as expected due to the smaller sensor pixels on the 808.

I’m going to put a stake in the ground and say that the 808 at 8MP will give you a better effective sensitivity for the same noise levels as the N8 at 12MP. My Estimate – 1 to 1.5 F-Stops. At 5MP, the advantage is going to be 2 or more F-Stops although this is just a guesstimate. At native resolutions, the N8 is significantly more sensitive, for the same noise levels.

The results means that fully zoomed images on the 808 are likely to be, at the low light levels I tested, more noisy and require a steadier hand.

Disclaimer – The above is based on just a handful of photos taken and analysed from the sample Nokia 808 devices at MWC, Feb 2012.

More features to think about…

  • Slide zoom. On-screen touch zoom feature looks easy to use.
  • Improved auto-focus. Should reduce ‘hunting’ in video and errors in photos.
  • Touch Autofocus in video
  • HDMI, TV out and DLNA for image and video display
  • 1080p at 30FPS with 4x zoom (12x zoom for 360p video – good enough for a casual 16:9 YouTube video)
  • LED light and Xenon flash
  • Equivalent 26mm wide angle – good for self-video and images.
  • High amplitude audio recording.

Possible issues

  • Macro mode only down to 15mm
  • Heavy smartphone.  Bulky. (But a very small and light compact camera)
  • No raw mode – Unlikely to be an issue for most people.
  • No optical stabilisation (which becomes important when zooming)
  • Zoom is not step-less
  • It’s Symbian. Who will develop apps for this?
  • 640×360 pixel screen is low resolution for the size.
  • Social client only supports Facebook and Twitter and is not open for third party developer integration
  • CPU is only 1.3Ghz ARM11 [Generations behind the current smartphones]

P1030295 P1030296P1030300P1030290

More of my Nokia 808 images from MWC here.

Summary.

The breakthrough in the Nokia 808 PureView is not so much the technique of pixel oversampling for zoom and noise reduction ( My compact sensor Panasonic FZ150 uses pixel oversampling for additional lossless zoom for example) but the way that it’s been taken to the next level and put into such a small form-factor is a breakthrough for pocketable cameras that we’re likely to see copied. Hybrid and highly pocketable tele / high mega-pixel pocket cameras are likely to appear very soon.

For those not using the ‘lossless’ zoom, the  808 offers ways to get low-noise images and better low-light sensitivity. The long focal length may be a useful feature for creative photographers but also increases the risk of out-of-focus subjects. Using the zoom feature will increase the noise and, in video, there’s a risk of a lot of camera shake. There doesn’t seem to be any burst photo mode or bracketing mode and macro mode is only down to 15cm. Photographers will notice these limits but they’re unlikely to affect consumers.

As a connected camera fan I’m excited by the Nokia 808. For photo-blogging at 3MP there’s going to be some exciting low-light possibilities or medium-range zoom possibilities and for daylight photography, 8MP images are going to blow-up well in prints. The Symbian OS could be a barrier for 3rd-party software though; a device as creative as this deserves much better. I can’t help thinking that there’s a niche chance for Symbian to become a connected camera operating system. If Nokia were to produce a real camera body with the same technology, more advanced camera control features a small optical zoom and some optical stabilisation, the photography community might be tempted to get behind this.

As it is though, it does look like I’ll be buying the Nokia 808 as soon as I have a chance and for anyone interested in ‘always there’ quality or ‘connected photography, it might even be worth buying the 808 just for that. The phone’s a bonus!

Advertisements