What is Pixel-Binning?
Nokia’s Lumia 808 and 1020 PureView smartphones come with a 41MP camera with 38 effective megapixels. Nokia has also wisely increased the sensor size so that it’s larger than most other compact camera’s.
Nokia says that the secret to great image quality with the PureView’s image sensor is oversampling. What the camera does is it captures data at 38MP (when shooting at the 4:3 aspect ratio), but then downsamples or pixel-bins the image to a default output of 5MP.
It does this by combining the information from several pixels to create a single pixel, in the case of 38MP to 5MP; seven pixels are combined into one. Nokia claims that by doing this, the PureView’s camera manages to retain image detail but reduce image noise.
Have you ever noticed that an image can look terrible when you look at it on a large monitor, but when it’s scaled down to the size of your smartphone it looks a lot better? That’s because the image’s imperfections have been reduced along with its size – as well as detail. This is one of the benefits you can get from down-sampling an image. If an image looks noisy at 38MP, it will look better at 5MP.