The HTC One has just introduced a new type of camera into the mobile market. HTC calls it UltraPixel, and it uses larger sensor pixels to offer much better low-light performance. But how does it compare to the PureView tech we saw in the Nokia 808 PureView and Nokia Lumia 920? Let's take a closer look.
Let’s Cut the Nonsense
Both HTC’s UltraPixel and Nokia’s PureView are marketing terms. They have no inherent meaning, which means that – like Apple’s “Retina” screens – what they define is flexible. This flexibility is doubly important when you look at the difference between the cameras of the Nokia 808 PureView and the Nokia Lumia 920. Both use PureView tech, but their cameras are entirely different.
Each tech takes its own approach to producing above-average photos without just piling on the megapixels. But which approach will be more successful? Let’s take a look.
HTC One – 4.3MP 1/3-inch CMOS BSI
Nokia Lumia 920 – 8.7MP 1/3-inch CMOS BSI
Nokia 808 PureView – 42MP 1/1.2” CMOS BSI
Looking at the pure sensor stats, the HTC One sounds positively awful, doesn’t it? The same size sensor as the Nokia Lumia 920 but with far fewer pixels – who would want that?
Although they’re touted as rival-bashing next generation camera, both the Nokia Lumia 920 and HTC One use sensors the same size as many of 2013’s biggest phones, such as the Sony Xperia Z. By traditional camera standards, they are tiny.
Conversely, the Nokia 808 PureView has a genuinely large sensor. At 1/1.2in, it’s a good deal larger than that that of most compact cameras. Of course, it’s also quite different from most “proper” camera sensors because it has to pack-in so many sensor pixels – 42 million.
All three sensors are back-illuminated, which aims to give better low-light performance. However, BSI sensors like these are common nowadays, used in most big-name expensive phones including the iPhone 5 and Google Nexus 4.
HTC One - 2.0 µm
Nokia Lumia 920 – 1.4 µm
Nokia 808 PureView – 1.4 µm, or up to 4.1 µm virtual
Pixel size is where the differences of the HTC One and Lumia 920 start to show more clearly. While the HTC one has far fewer pixels, they’re much larger than the average size, letting them take in far more light than a normal-sized phone sensor pixel. HTC claims 300 per cent more light.
This should result in much better low-light performance, although it could also result in worse pictures during daytime unless HTC’s picture processing is particularly good.
It is at the pixel level where the Nokia Lumia 920 looks pedestrian. With 1.4 µm pixels, the teeny-tiny components that make up its camera sensor aren’t anything out of the norm.
Once again, the Nokia 808 PureView excels with its over-the-top mega-sensor. The pixels that feature are actually the same size as those of the Lumia 920, but there’s a ridiculous amount of them. There’s an image processing engine built into the camera that lets the 808 downsample images, making pixel clusters essentially function as a single pixel.
For example, when shooting a 5-megapixel image, the 808 PureView’s “virtual” pixels are more than twice the size of the HTC One’s.
Why use virtual pixels instead of much bigger ones? This lets the Nokia 808 PureView offer much better digital zoom than any other phone camera, because it can simply crop into the sensor, reaping a high-resolution even when using just a fraction of the entire image sensor.
We’ll have to see whether the true larger pixels of the HTC One perform better than the Nokia 808 PureView’s virtual ones when we get a review sample in.
HTC One – f/2.0, 5-element construction, 28mm focal length equiv.
Nokia Lumia 920 – f/2.0, 5-element construction, 26mm focal length equiv.
Nokia 808 PureView – f/2.4, 5-element construction, 28mm focal length equiv.
The focal lengths and element construction of the three phones are pretty similar. Each uses a 5-element lens with a wide focal length. The Nokia Lumia 920 is slight wider, with an equivalent focal length of 26mm against the 28mm of the Nokia 808 PureView.
Where the Nokias and the HTC One differ is in their lens apertures. We judge the lens by its f-stop rating, which indicates how “fast” it is, how much light it can take in within a certain exposure time. Suprisingly enough, the HTC One and Nokia Lumia 920 are slightly higher faster than the Nokia 808 PureView.
The two quicker phones both use f/2.0 lenses, while the Nokia 808 PureView is an f/2.4 lens. F/2.0 lenses are particularly quick among currently-available mobile phones, and even some of this year’s top mobiles are stuck a worse apertures, such as the Sony Xperia Z’s f/2.4 rating.
HTC One – Live HDR video recording, integrated HDR, image stabilisation, simultaneous video/stills capture, LED flash
Nokia Lumia 920 – “Lenses” camera modes, LED flash, image stabilisation
Nokia 808 PureView – Xenon flash
So far the Nokia Lumia 920 seems pretty ordinary. It has a decent sensor and lens, but what’s so special about it? The phone uses optical image stabilisation to let it use longer exposure times, by compensating for the small movements we unavoidably make when… doing anything.
Of course, the downside to this method of improving image quality is that it doesn’t account for movement on the other side of the camera. If whoever you’re snapping is jumping around, expect blurry results.
This stabilisation is found in the Nokia 808 PureView and HTC One too, so while it differentiates the Lumia 920 from the smartphone pack, it’s nothing too exciting within this crowd.
The HTC One marks itself out here with some hardware-intensive software modes – most exciting of all is live HDR video. This merges two exposures to increase detail in captured images. This is a mode you can use for stills too. The Nokia Lumia 920 and PureView 808 do not offer HDR modes as standard, which is a bit of a bummer.
The Nokia 808 PureView exits stage left with one last stand-out feature, a Xenon flash. This is the kind of flash “proper” cameras use, while the Lumia 920 and HTC One make do with the LED “torches” you’ll find on common smartphones.
PureView or UltraPixel - Which is the best?
As this article should make abundantly clear, Nokia has already diluted the meaning of its PureView technology with the Nokia Lumia 920. It features little of the photo magic of the Nokia 808 PureView, even if it does offer significant real-world photographic benefits in low light.
The HTC One is technologically much more interesting than the Nokia Lumia 920, offering all of its photo benefits with larger pixels that dramatically change the way it captures photos. However, for our money the Nokia 808 PureView’s snapper is still the most intriguing of the bunch, enabling a decent-quality digital zoom and excellent photo quality. Roll on the Nokia EOS, which is rumoured to use the same photo tech as the 808 PureView, but with Windows Phone 8 software in place of Symbian.