Samsung continues to announce ultra-high resolution camera sensors aimed at affordable markets. The company just launched the Samsung ISOCELL HP3, a 200 Megapixel camera sensor featuring exceptionally small sensing pixels. The thing is: smaller pixels aren’t always better, as their size makes it increasingly more difficult to gather photos.
Each pixel is only 0.56 μm (square), which is tiny, so there’s a 4:1 pixel-binning mode that would equate to a 50 Megapixel sensor with 1.12μm pixels, or even a 16:1 pixel binning that approximates a 12.5 MP sensor with 2.24μm pixels.
It is also very impressive that the sensor features quarter-resolution pixel-level phase detection autofocus. Each group of 2×2 pixels requires an insanely small lens to achieve that.
Samsung calls this its pixel-binning feature “Tetra pixel,” but the principle is the same as we’ve seen before. Each sensor maker has a different implementation and would create a brand, perhaps for intellectual property or marketing reasons.
It’s important to understand that binning sixteen 0.56 μm pixels into one virtual 2.24μm pixel isn’t the same as one physical 2.24μm pixel. That’s because each 0.56 μm pixel requires some supporting electronics, and some sensing area of the chip might be lost to that. The more pixels you have, the more wires and other things might eat up some sensing area.
The additional electronics might also increase the chance of introducing (electronic) noise that might affect the sensor’s performance. Smaller pixels might also affect the effective dynamic range of the sensor, but fortunately, that might be compensated by capturing more HDR frames using stacked photography.
In the past, we’ve seen degrading performance with some 0.7 μm, so I wonder if this sensor would bump into similar issues.
These ever-smaller pixels allow smartphone OEMs to market affordable camera phones with high Megapixel specifications. That said, it remains to be seen if we’re going to see proportional image quality gains, especially in low-light.
Still, depending on where it is used, this sensor could be an improvement over past sensors at the same price point. For example, it could be slightly larger or capable of faster readouts, allowing 8K recording (or 4K in slow-motion) smartphones at a given price range were not capable of before.