Nokia’s PureView technology has raised many eyebrows in the smartphone industry, with experts and consumers alike both impressed with the results and intrigued by how they are achieved.

Revolution in Imaging

A revolution in imaging PureView Pro imaging technology doesn’t represent a step change for camera smartphones performance, so much as a quantum leap forward. The first device to feature Nokia PureView Pro camera technology is the Nokia 808 PureView, which gives people the means to take better images and video footage than ever before.

Nokia PureView Pro turns conventional thinking on its head. It dispenses with the usual scaling/interpolation model of digital zoom used in virtually all smartphones, as well as optical zoom used in most digital cameras, where a series of lens elements moves back and forth to vary the magnification and field of view. Instead, we’ve taken a completely new road.

Unprecedented camera control and versatility, combined with truly spectacular-quality images and video. Nokia 808 PureView sets new industry standards — it will give you around 3x lossless zoom for stills, and 4x zoom in full HD 1080p. For 720p HD video, you’re looking at 6x lossless zoom.
And for nHD (640×360) video, an amazing 12x zoom!

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 below :

What happens next depends on the settings and whether or not you’re using zoom. But to give you an idea, the default still image setting is 5Mpix at 16:9, and for video it’s 1080p at 30fps. Using these settings, the zoom is around 3x for stills and 4x for video. Conventional zoom tends to scale up images from a relatively low resolution, resulting in poor image quality. We were convinced there must be a better way, and we found it.

In an easily Understandable way….

In creating PureView, the manufacturer was reacting to what it has said are consumer demands for, amongst other things, better zoom capabilities on smartphones. At the moment most cameraphones use digital zoom which produces poor quality results, effectively enlarging a part of an image and reducing the number of pixels that can be shown. The alternative, optical zoom, uses a series of lenses to magnify an image so that the number of pixels used in the final photograph remains the same.
Optical Zoom
Optical zoom is something that has been used in mobile phone cameras before, with Nokia’s own N90 featuring a long zoom lens mounted across the phone’s body, but the technology is cumbersome and not ideally suited for slim handsets.

With PureView, Nokia has used a system called oversampling, which takes the original 41megapixels captured with the 808’s enormous sensor and reduces them to a high-quality image consisting of only five megapixels. Pixels are pulled together into groups of seven and those seven pixels are then condensed into one, so that even though the resulting photograph is only a five megapixel image it is of a better quality than those captured with more traditional five megapixel cameras.

 When zoomed in, the seven pixels that originally form that basis of each pixel in the final image are reduced in number, so zooming in half way means that perhaps three or four pixels are condensed into one for the final image. Maximum zoom involves focussing on a five megapixel segment of the full 41 megapixel layout, with no oversampling occurring but a detailed, high-quality image still being produced which is far better than could be achieved with normal digital zoom.

Beyond the actual megapixels being used, Nokia also equips its smartphones with Carl Zeiss lenses, something which can greatly enhance the quality of the final image. The 808 PureView has a f2.4 lens which makes it good for low lighting conditions and excellent for reducing camera shake since the shutter does not have to be open for as long when capturing a shot.

PureView in Lumia 920
The Lumia 920 features PureView technology, but does not have the same 41megapixel sensor seen on the 808 PureView. How Nokia’s photographic capabilities will transfer to these new devices remains to be seen as there will not be anywhere near as many pixels available for oversampling, but the manufacturer has already been boasting about its new phones’ imaging prowess, despite some examples being a little misleading.

Courtesy: i.nokia.com,  wpsuperfanboy.com

Posted by

Mahesh.P

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