Since HTC promotes that the One's 4MP sensor is more sensitive to light, we decided to test its low-light shooting capabilities in an extremely dark environment. However, it seems that the larger photosites don't make much of a difference here; the One's low-light gathering abilities aren't much better than the rest. We then pushed up the shadows and brought down the highlights using Photoshop's Shadows/Highlights tool, set to a maximum of 100%, to see if the details were hidden in the shadows. But here again, it seems that the larger photosites don't add much to the One's dynamic range.
In fact, the Nokia Lumia 920 (the Nokia 808 PureView's results are so good, it's getting ridiculous to compare any other phone's camera against it) does much better than the HTC One at both low-light capture and the ability to pull details from the shadows and highlights. But the Nokia Lumia 920 takes more chances; it consistently opens its shutter for a longer period of time than the One, capturing more light but at the risk of introducing camera shake into the picture.
Since we couldn't manually dictate shutter speeds for the phones, this isn't a strict 1:1 comparison. But from what we can see, the HTC One doesn't offer significantly better low-light performance than its peers.
We took the low-light shots, pulled out the shadows and pushed down the highlights in Photoshop CS4 to see what we could see, which wasn't much. Here we show you the HTC One's ISO 100-1600 shots after post-production, with comparisons against the better-performing Nokia 920's shots. Note however, that the Nokia 920 is consistently shooting at slower shutter speeds than the HTC One, which allows it to capture more light. At ISO 100 for example, the HTC One is shooting at 1/20 of a second, while the Nokia 920 is shooting at a very risky 1/3 of a second.
We also threw in the Nokia 808's to show you just how ridiculously it's outperforming everyone else.