UltraPixels: How HTC wants to redefine the smartphone camera
Pulling sharply into focus in the new HTC One is the camera. As we exclusively revealed in early February, HTC has introduced "UltraPixels" in a move to "tackle the megapixel myth", as Symon Whitehorn, HTC photography ninja, told us before the launch of the new HTC One.
HTC has been showing plenty of interest in the cameras on its smartphones, with the introduction of the HTC ImageChip in 2012 in the HTC One X, and subsequently the boosting of the front-facing camera on the One X+, along with continuing refinements in focusing speed, burst capture and so on.
In the HTC One, however, HTC is taking a gamble. Stepping away from the conventional route of boasting about a newer, higher resolution sensor, HTC is taking a different tack. The result is the UltraPixel sensor. We sat down with Symon Whitehorn to get all the details on HTC's new camera.
What is an UltraPixel?
People have been talking about the megapixel race for several years. It has been prolific in digital cameras, calming down in many compact cameras around 2010, but continuing to run in smartphones unabated.
The problem is that increasing the number of pixels crammed on to a sensor's surface is doing nothing for image quality: the numbers might sound impressive, but it means that the pixels are getting smaller and are less able to perform their primary function - absorbing light.
The analogy that Whitehorn uses to illustrate this point is one of catching rain. You can put down a bucket, or you can put down lots of cups. They'll take up the same floor space, but the bucket catches more rain, as the spaces between the cups mean that lots of the rain misses the target.
The same notion is applied to light on HTC's UltraPixel sensor. In terms of resolution it's only a 4-megapixel sensor, but the size of the pixels is larger. "We have a 2.0 micron pixel size," says Whitehorn, which is comparable to the pixel size on enthusiast compacts, such as the Fujifilm X10, which has a pixel size of 2.2 microns.
Why is HTC doing this?
The aim of having larger pixels is to preserve the wavelength of light. A larger pixel can take in more light and, as Whitehorn says, "light is data". The problem with crammed sensors is that the light falling outside of the sensitive areas just becomes noise, because there's a lack of data.
The move should result in a sensor that reduces signal noise and increases the dynamic range, so that the HTC One will perform better in tricky situations, such as in low light and, HTC claims, with fast-moving subjects. That's jumping dogs, running children or friends in the pub in real, social, terms.
The advantage of having fewer pixels is that there's also less data to process: you have smaller file sizes, but with what ought to be better-quality images within. And 4-megapixels is still twice that of a 1080p HD TV, so it's not lacking is resolution for most applications, like sharing on Facebook or Twitter.
Components of the camera
But the sensor is only one aspect of the HTC One camera. Just like other cameras, there are four elements that pull together to work in harmony. In the HTC One it's the lens, the f/2.0 aperture, the UltraPixel sensor and the HTC ImageChip.
The lens is matched to the sensor and is an equally important part of the puzzle. It actually comes from the same manufacturer used by Apple on the iPhone 5, claims Whitehorn, and is optical-grade plastic rather than glass.
The f/2.0 aperture is designed to let in as much light as possible and, given the small sizes involved, the aim is not to produce a pronounced bokeh effect as you might get from that equivalent aperture on a larger-sensor compact or DSLR camera, but simply to give the sensor the best chance of resolving the scene in front of it with maximum light.
Finally the HTC ImageChip is the imaging processor that pulls all the raw data together, processes it, and outputs your JPEG image. However the raw files are not available, before you get overexcited. With plenty of power on offer, the HTC One camera will not only give you HDR (high dynamic range) shooting in stills, but also in video, at full HD.
The ImageChip works not only on the rear camera, but also on the front 2.1-megapixel camera. This wide-angle lens is corrected to remove the typical distortion found on wide-angle lenses at close range. We saw the same arrangement on the HTC One X+ in 2012 and found the improvement to be dramatic over a typical front-camera arrangement.
Sensor-based optical image stabilisation is also in place, which works at a high 2000Hz frequency on a dual axis to help keep those shaky moments stable.
Software magic: Zoe Camera
But the technology only brings so much to the table. As with previous devices, HTC has worked to make the camera app as convenient as possible. You get instant access to both video capture and stills shooting with buttons right in the display.
You get the regular run of features you'd expect, like continuous autofocus in video, touch focusing, panorama and the rest, however it's a new shooting mode called Zoe Camera that will get you excited.
The name Zoe is derived from the zoetrope and like this device, Zoe Camera will make moving images out of still. What Zoe Camera actually does is continually record video whilst you have the app open. You can still snap pictures, but Zoe is buffering 3 seconds of footage around what you are shooting, keeping extras to bring scenes to life.
What is results in is a zero-edit funky video at the end. It will incorporate the pictures you've taken, but animate around them, add effects and themes, as well as music, to dramatic effect. It's a great feature, designed to make sharing more interesting than just posting a couple of photos up on Facebook. Instead you'll have a cool video that looks like it's taken hours to cut together, but in fact is done in-phone, and almost instantly.
READ: Hands-on: HTC One review
The risks that HTC is taking with the camera make sense to us. Small files will be better for storage and sharing, and there's innovation at the end of the process too. Of course the proof of the pudding is in the eating, so we'll be bringing you a performance comparison and more detailed examination in our HTC One review when final devices become available.