Tuesday, February 28, 2012

Pixel Binning is Here!

Nokia 808 PureView, photo courtesy of Nokia

With the announcement of Nokia’s new camera/cell phone combo, the 808 PureView with a sensor resolution of 41 MP, the subject of pixel binning is becoming a hot topic. Starting with a physically large sensor—somewhere in size between the usual digital compacts and APS-C sensors—the 808 will offer uncommonly high resolution images, lossless digital 3X zooming, a 5-element Carl Zeiss lens, and exceptional low light performance. It’s this last quality where pixel binning comes into play.

Pixel binning has been used in astro-photography and micro-photography. In pixel binning, adjacent pixels are processed and combined into one large sensor, sometimes called a “super pixel.” The advantage of this is when you combine the light gathering capabilities of four pixels into one, you increase the amount of light you are working with in the image. So, the result is reduced noise in the image. That’s why it is used in astro-photography, where you have very low light subjects and a lot of black in the image. You end up with noise-less, clean images. Turns out, it works in regular photography, too.

Photo taken with Nokia 808 PureView, courtesy of Nokia

Nokia uses the same technology in the 808 PureView, though they are not saying exactly how many pixels are being combined into one super pixel. However, the samples they are showing makes the reduction of noise significant in the 808. But nothing can be gained without some costs, and in this case, the cost is resolution. This makes sense, because when you have to use several pixels to give you, in the end, one pixel of resolution, you will need to start off with a lot of pixels to end up with anything useful. So in the case of the Nokia 808 PureView, though the sensor is 41 MP, with pixel binning you will actually be shooting in resolutions of no more than 8 MP. That’s quite a drop, but what you gain is a very clean image with little or no noise. And this is what most photographers seem to be asking from their cameras, to be able to shoot at lower light levels and still have noise-free images. Pixel binning is the way to achieve this and without a doubt, this technology will be used in more cameras in the near future.
 Example of Pixel Binning, photo courtesy of Fujifilm

Sony is rumored to be using pixel binning in their compact cameras coming out later this year. It makes sense that this will show up in DSLRs, especially for cameras targeting photojournalists. It wouldn’t surprise me that this is why the new full-frame Canon EOS-1D X has a sensor resolution of 18 MP. Maybe it actually has a much higher resolution sensor but uses pixel binning to reduce noise and the pixel count down to that 18 MP. That would make sense, but of course, I have no idea if this is true. It’s just a thought that occurred to me. Anyway, pixel binning is here and it’s a good idea. You will be seeing more of it.