Mobile cameras are one of the most popular aspects for manufacturers. First there was the war of megapixels, then that of infinite sensors, later we saw camera modules of different types and now the one-inch sensors triumph. In short, the main brands want to offer a device capable of taking high quality photos. And, for this, they use a technique called “Pixel Binning” which the quality of the photos has improved without us realizing it.
you are probably wondering what is pixel binninghow it works and the main advantages provided by this technique that our mobile uses to improve the general quality of our photos.
What is pixel binning, the secret weapon of mobile cameras
First of all, we must start with a little theory. The megapixels of a photograph represents the number of pixels that compose it, and the higher this value, the greater the final result. Of course, without implying that a photo with more megapixels is always better, since the quality depends on many other factors. However, the growth in mobile camera resolution means that those millions of pixels can serve another purpose.
Here the binning arises, the process by which adjacent pixels are joined of an image to create a larger pixel, or super pixel. However, this technique is very useful because of the high resolutions of current sensors, and depending on this, these units (pixels) are grouped in different ways.
For example, the recent Samsung Galaxy S23 Ultra combines up to 16 adjacent pixels, using the 200MP sensor, resulting in a 12.5MP photo. Another example is given in Google Pixel, the Pixel 7 and Pixel 7 Pro group the 50 megapixels into groups of four, also returning a 12.5 image.
This is the moment you ask yourself… Why waste so many megapixels if the camera can take high resolution photos? Well, here’s the crux of the matter, and that’s the usefulness and function of pixel grouping.
Pixel size, crucial for capturing light
The short and simple answer is: with binning we lose in resolution but we gain in light, who is primarily responsible for photography. If you’re looking for something more advanced, keep reading.
Checking out the interview with Judd Heape, vice president of camera (among other aspects) and video products at Qualcomm, we’ll better understand the science of it all. His response emphasizes light sensitivity and space constraints.
The sensors of our mobile cameras have many pixels, these, as they grow, improve the details of photography, as we already know. However, also hampers sensor performance in low light conditionsso the dynamic range is compromised.
By adding more pixels, these are smaller because they fit in the same space (which is limited today with current technology), and these smaller units “cannot capture as much light”, explains the Qualcomm executive.
Pixel size is measured in micrometers (μm), so you could say that a sensor with 1μm pixels absorbs less light than one with 1.2μm. What happens then? Well, camera makers are taking various measures to combat this problem.
When space matters
One of the remedies is to use the computational photography, which combines several images into a single one, the latter containing the data of the preceding ones. It is not the only ‘life saver’ and it is possible to increase the size of the sensor.
We return to Google to provide an example of this practice. The Pixel 7 uses a 1/1.31-inch sensor for its main camera, so the pixels on it are larger and collect more light. Like everything in this life, this has its consequences: now the problem is space.
Google engineers had to work hard to design their latest phone because with this larger sensor they had to find space to accommodate the rest material photographic. This results in fewer places available for other important parts, such as the drums which take up most of the body. This is where the characteristic bulge of the Google Pixel camera comes from.
How pixel grouping works
As we have already commented, pixel grouping forms “super pixels” by nesting them all into one. By combining them, this super pixel gains in sensitivity to light, the product of the sum of each of the components. Another factor also comes into play: the wavelength of light it is captured in different ways by each pixel.
Typically, 25% of pixels capture red light, 25% blue, and the remaining 50% green. When our mobile uses this technique, the ISP or image signal processor (for its acronym in English) makes it possible to enter sets of four (nine or 16) adjacent pixels to obtain image data. Heape comments that this compensate for the result by lowering the resolutionbut increasing sensitivity to light.
Likewise, the expansion performance of a sensor to enlarge pixels cannot be exactly reproduced by pixel binning, because with this union artifacts are generated in the image. Fortunately, artificial intelligence has helped in this area by reducing these artifacts to a minimum.
This is how the hundreds of megapixels are used, but it is not the only function
Although this somewhat compensates for the lack of small sensors in smartphones, that these carry sensors that accumulate hundreds of megapixels they not only benefit photos with more light.
And there we stop talking about photography for go to the video. The latest sensors enable tasks not exclusive to larger ones, such as high-resolution video recording. The era of 8K has arrived and Samsung has confirmed it, since the Galaxy S23 Ultra can record video at this resolution, something that would be impossible if the sensors had stuck to lower resolutions (and even if they increase pixel size, it’s not possible either).
Megapixel growth brings us two benefits: better pixel binning and 8K video
On the other hand, higher resolution brings us closer to telephoto lensesbecause “under adequate lighting conditions” we can take advantage of high resolutions to obtain a good quality digital zoom.
There is no doubt that pixel binning was able to accompany the growth of the resolution, making the most of it and compensating for the problem of having smaller disks. This “trick” has been with us for a few years, and it looks like it will last a long time.
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