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Taking PureView to the next level

Ian Delaney Published by Ian Delaney September 05, 2012

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Taking PureView to the next level

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477

Ian Delaney Published by Ian Delaney September 05, 2012

After the tremendous reception deservedly received for the Nokia 808 PureView, our imaging team was perhaps entitled to a holiday.

Instead, though, we sent them back to the lab to work on two things: bringing the technology to Lumia smartphones and delivering a whole new set of improvements.

Carl Zeiss Optics

Optical Image Stabiliser: Barrel shift type

Stabiliser performance: Up to 3EV (8x longer shutter speeds)

Focal length: 3.73mm

35mm equivalent focal length: 26mm for 16:9, 28mm for 4:3

F-number: f/2.0

Focus range: 8 cm – Infinity

Construction: Five elements, one group. All lens surfaces are aspherical

Optical format: 1/3″

The results of this intensive labour are first found in the Nokia Lumia 920.

[NB: If you want to get right into the nitty-gritty, download and digest the white paper. This is the tl;dr version.]

The initial PureView model focused on the problem of digital zoom and perfect details. Phase two of development focuses on low light performance, and adds more practical features that will allow more camera phone users to take better pictures.

The number one camera phone annoyance – fixed

Low light performance has been improved through two particular measures.

First, the sensor type has been changed. A next-generation Back-Side Illuminated sensor is fitted that places the photosensitive area directly beneath the lens, without wires or metal between, as is the case with Front-Side Illuminated sensors. More light reaches the plate, in other words. That’s of critical importance when there isn’t much light around.

Image captured with Nokia Lumia 920

Image captured with competing high-end smartphone

Second, we’ve adopted a massive f/2.0 aperture – in layman’s terms, it’s a bigger hole, and so it lets in more light from the start when you’re using it indoors. Both these measures mean a lower sensor size is needed in order to get great results when you’re working in low light.

Ready, steady, snap

These advances are complemented by Optical Image Stabilization (OIS). Your pictures and videos won’t blur when your hands are shaking, or when you are on the move. Again, it’ll help in low-light conditions where exposure times can get significantly longer.

Your images and pictures won’t blur

(Updated caption) Image capture with Nokia Lumia 920 – WITHOUT Flash

Image captured with competing high-end smartphone

The OIS technology isn’t a digital algorithm, like you may have experienced previously. Crucially the rear-end of the camera is caged with a gyroscope to move the whole optical assembly to compensate unintended camera movement. Enough explanation: this video tells the story best.

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This is a simulation of OIS technology.

As a self-confessed terrible photographer, thanks to genetically inherited shaky hands, it’s this part of the story that interests me the most.

But there’s more…

The Nokia Lumia 920 packs a new generation of LED flash. This can be used as a continuous light for video and – for the first time – a pulse burst flash. The technology behind LED flash has improved significantly over a period of mere months, to be able to accurately freeze subjects under many more conditions than used to be the case.

Next, the image processing algorithms on the Lumia 920 significantly outshine any found on previous camera phones. In particular, the ‘denoise’ algorithm for reducing any visual noise from images is brand new and better than ever. These advanced algorithms compensate for not having the oversampling technology used in the previous generation of PureView.

Once more, we’d urge the true camera-fanatics to take a look at the white paper for more in-depth information. Even if you’re not, there’s a ton of information there that’s just plain fascinating for anyone with an interest in photography.

Note: The Lumia 920 pictures in this post were taken using prototype hardware and software, and then reduced dramatically in size. In addition, the OIS video, above, was not shot using the Lumia 920. We apologise for any confusion on this point.

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