DxOMark chart shows that overall scores for smartphone cameras have steadily improved over the last 5 years.

If you're looking for the most drastic and impressive improvements in the world of imaging, the (sad?) fact is, you'll want to look at smartphone manufacturers. And this is what DxOMark highlights in a fascinating retrospective titled "Disruptive technologies in mobile imaging" that looks back on 5 years of testing smartphone cameras.

Not that the Sonys and Nikons and Canons of the world haven't made improvements—and who knows when the next generational leap in image sensor technology will take place—but as the saying goes: necessity is the mother of invention. Given the size limitations of our ever-thinner and lighter smartphones, its phone manufacturers who have had to be most creative when it comes to improving image quality.

That, in a nutshell, is what DxOMark breaks down in its retrospective, taking a close look at everything from how smartphones have improved their ability to eliminate noise without losing texture, to exposure improvements, autofocus, video stabilization, zoom, and the recent advancements in bokeh simulation.

Exposure is one of the areas that has seen drastic improvements. These images were captured at just 1 Lux, showing how the 808 PureView falls far short of the iPhone 5s, which in turn falls significantly short of the Galaxy S7 "thanks to better tuning and noise reduction."

The area where smartphone cameras seem to have improved most is in their ability to toe the line between decreasing noise and maintaining texture. Without simply increasing the size of the image sensor, this is a difficult balance to strike if you're using just image processing, so newer phones take care of this in three ways:

  1. Optical image stabilization to allow for longer hand-held exposures
  2. Temporal noise reduction (TNR) that combines image data from multiple frames
  3. Multiple camera modules (currently dual, maybe soon triple)

These techniques have helped manufacturers make huge leaps forward in the past 5 years:

This side-by-side comparison shows just how much better the iPhone X is at avoiding and cleaning up noise than the iPhone 5s. But even the iPhone6, which used the same camera module as the 5s, benefitted greatly from improved software.
But the iPhone X isn't even the best at this trick. Here it is compared to the Samsung Galaxy Note 8, Google Pixel 2, and Huawei Mate 10 Pro.

DxOMark's conclusion after sharing all of this data is unsurprising, and one of the reasons why we're keeping such a close eye on the newest smartphone camera tech:

We can see that camera hardware and image processing have been evolving alongside each during the past 5 years, and at a much faster pace than in the “traditional” camera sector.

DSLRs and mirrorless system cameras are still clearly ahead in some areas, but in terms of image processing, Canon, Nikon, Pentax, and the other players in the DSC market are behind what Apple, Samsung, Google, and Huawei can do. Thanks to their hardware advantages, the larger cameras don’t actually need the same level of pixel processing as smartphones to produce great images, but there is no denying that the performance gap between smartphones and DSLRs is narrowing.

That's a good summary, but if you want to dive into all of the comparisons—between phones of the past and today, and between the best phones on the market right now—head over to DxOMark and read their full retrospective.