Last year, the 40MP smartphone returned five years to the table Nokia Lumia 1020 delivered a 41MP camera. The ante has since been picked up considerably, as it did Huawei, Xiaomi, and others offer 48MP cameras.
But in an interview with MySmartPrice last month, a Qualcomm Executives claim that phones come with 64MP and 100MP sensors. In fact, the executive said at the end that a number of OEMs would release 64MP and 100MP + cameras by the end of 2019. A phone with a 100MP + sensor in particular sounds like a terrible idea, and here's why.
Smartphone camera ears should be very thin and small to fit into today's smartphone designs. This reduced size means the sensor says photo sites or pixels – actually used to capture light – should also be cut in size. Smaller photosites / pixels are simply incapable of capturing as much light as larger, making a big difference in low light. Sensor manufacturers have traditionally been caught using very small pixels (higher resolution that go worse at night) or fewer, larger pixels (a lower resolution that do better at night).
However, in the past year, smartphone sensors have started using pixel binning technology to combine four pixel data into one "super pixel". It comes at the expense of resolution, with the output resolution usually a quarter of the sensor's maximum resolution. Sony's IMX586 48MP camera sensor is a great example of this technology, as the pixels are very small (0.8 micron), but pixel binning basically produces the equivalent of 12MP 1.6 micron pixel image.
The biggest challenge is to fit all the pixels into a smart phone sensor. One solution is to increase the size of the sensor to accommodate all of these pixels, while still maintaining the size of the pixel, which causes a massive camera. Another option is to dramatically reduce the size of the pixels while relying pixel binning for low light shots.
A 100MP smartphone camera will probably make pixels that are too small for even pixel binning to make a big difference.
As we know it today, pixel binning may not produce good results with a 100MP camera, as the pixels may be too much. A 100MP camera sensor with 0.3 or 0.4 micron pixels will essentially produce pixel-binned results equivalent to a 25MP 0.6-micron or 0.8-micron camera. It looks like a lot of work for inferior low light results, especially when compared to phones like the Galaxy S10 Plus and Pixel 3. Both of these devices offer a 12MP 1.4-micron pixel main camera. Heck, that OnePlus 6T and its 16MP 1.22-micron pixel camera also looks as though it will offer better paper results than a 100MP pixel-binned camera.
Even if 100MP smartphones have a much larger sensor size and only a slight decrease in pixel size (up to 0.5 or 0.6 micron pixels), you still look for results that effectively the equivalent of a 25MP 1 or 1.2 micron pixel camera – a way of 48MP phones. The difference is that you now have a huge camera push. But at least you have a lot of loose detail during the day, right?
Another important consideration with 100MP smartphones is their output file size. Your typical 40MP shot at a Huawei flagship can range from 7MB to 15MB. This means you can potentially look at a 100MP snap, with more than double the size, over 30MB per snap. This is before you get to the RAW area, with the Galaxy S8The RAW snaps will come just below 24MB, while the Mate 20 Pro's DNG imagery weighs at about 80 MB. A RAW image taken by a 100MP camera will no doubt be exponentially larger.
It is noteworthy that the 48MP and 40MP smartphones usually shot at their pixel-binned resolution today, so we'd expect the same from 100MP phones. You can still expect a significant file size increase, as these phones are likely to be shot with a pixel-innermost 25MP. There are also technologies like the heif format to reduce file sizes while maintaining image quality. Obviously any 100MP phone without this technology needs almost a ton of storage.
We also need to consider image processing. Big smartphone photography is more than just a simple scene capture, such as multi-frame processing, machine learning, image segmentation and other techniques are the lifeblood of the best mobile cameras. Today's ultra-high resolution smartphones can indeed deliver pixel shots that get the full processing. But few chips today provide support for processed 48MP snaps, leaving processing at even higher resolutions.
Speaking of slides, horsepower is another challenge for 100MP smartphones. Qualcomm has already claimed to support 192MP Photo's (ie images without additional processing) with its recent SoCs, but execution is another question. Using the Mate 20 Pro's RAW already leads to a short "save" notification and a degree of delay. We also saw the Nokia 9 PureView Handle a ton of image data, albeit from different cameras, as it is necessary to process and actually save these snaps.
All this is not to say that there is no benefit to offering a 100MP smartphone camera. The main advantage is that you can get enough solved details for zooming all day long. But why go when today's smartphones offer telephonic secondary cameras and even periscope zoom anyway? Unless sensor manufacturers have emerged a whole new way to distill 100MP of information into a good night shot, it looks like a bad idea.
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