When a smartphone shouts about its camera as being something special it turns a lot of heads. We've already seen and reviewed the HTC One and love it as a smartphone. It's an ace device. But what of its "Ultrapixel" camera - is it really as "ultra" as it proclaims? We've spent a week living with the HTC One and used it as a camera - with some of the obvious smartphone content-sharing features of course - to see whether it switched us on or off.
'Ultrapixel': HTC's megapixel marketing
Megapixel is a term used to describe one million pixels. Ultrapixel - the way HTC describes the One's camera - is a marketing term; a brand name with the goal of attempting to upsell the megapixel.
Any claim that the One has a 4-ultrapixel camera means, in reality, that is has a 4-megapixel camera. Nothing more. But the crucial difference is that those "pixels" are each larger than most smartphone competitor models - often twice as large - because there are less of them on the same size surface area. That makes the One more effective at capturing light which is useful for a couple of key things: reducing noise - that mottled, colour-flecked nastiness that you sometimes see in images - and potentially increasing dynamic range for a better black-to-white range.
The concept is theoretically sound and we were expecting great things. But the problem is the camera has a mere 4-megapixels of resolution. That's about a third the output offered by most compact cameras, or half the number compared to, say, the iPhone 5 and plenty of similar smartphone competitors. These higher-resolution models have their own issues, of course, by having more resolution than is really necessary to the detriment of quality.
READ: Apple iPhone 5 camera review
But has HTC forgotten that resolution plays a key function? Think about the logic of standard definition versus high definition - click on BBC One, then BBC One HD and admire all the news readers' crowsfeet in extra detail - and it speaks for itself.
Greater resolution opens up potential for greater detail. Of course there are all kinds of things that get in the way of reproducing full resolution - lens sharpness, low-pass filter diffusion, bayer array colour calculations, signal amplification, individual companies' processing methods and that sharpness is, in part, perceptive and based on processing methods. These points combined can ultimately make for a less than perfect result, increase image noise and heighten processing artefacts.
Still, resolution is crucial. You wouldn't go out and buy a one-megapixel camera because it's not really useful for much. And here's the next thing to think about: the HTC One's 16:9 camera sensor offers up the full four megapixels of resolution only in that "widescreen" format, just like a movie still. Many photographers will shoot at a 3:2 ratio and, in doing so, will sacrifice yet more resolution - it's cut to 3-megapixels, or a further 25 per cent loss - and introduce an effective shift in focal length too.
To explain that last point: the HTC One has a 28mm medium-wide lens without an optical zoom. By cutting away the outer edges of a shot in either the "regular (3:2)" or square (1:1) crops the impression you'll get is that less fits into the frame - you won't be able to fit as much into the shot without stepping back, which gives an equivalent longer focal length.
Zoom at your peril
Sometimes you will want to zoom in on further away subjects so that they fill the frame yet more, but without an optical zoom it's not really possible to do so. Technology dictates - at least at present - that an optical zoom on a smartphone would be too sizeable and expensive. It just wouldn't really work. The answer? Digital zoom.
But when we think about what digital zoom is, it becomes apparent why you won't really want to use it. All the HTC One can do is crop into the sensor size. Imaging you had a sheet of paper with an photograph on, but only wanted to have your best mate's face from the centre of that shot in the frame. Get out those imaginary scissors and cut it down to size - that's great, sorted, but now you have a much smaller sheet of paper. Stretching it back up to the original size would mean each dot that makes up that image is also stretched considerably - by up to four times its original size - and that makes everything look soft and lacking in detail.
This is exactly what the HTC One does. When zooming in by 4x - to provide a greater-than-112mm focal length equivalent - images are upscaled poorly and really aren't nice to look at. It's a predictable outcome given the sensor dimensions and resolution - and one that any given manufacturer will have to deal with.
But here's the thing, other companies have also thought outside the box before. The Nokia 808 PureView, for example, has a 41-megapixel sensor with "pixels" the same size as those in an iPhone 4S because the sensor is physically so much larger than in any other smartphone. Here digital zoom is used but provides an effective zoom solution without being disruptive to image quality - there's no need to upscale as resulting images still have a usable output size.
READ: Nokia 808 PureView review
But the 808 failed. It just wasn't commercially successful, ran on an out-of-date operating system and its camera - despite having the best sensor we've seen in a smartphone - had plenty of room for improvement when it came to the software and processing side of things.
What we think HTC ought to have opted in for is a half-way solution - it has used a physically larger sensor size with double the resolution but still in keeping with its larger-than-competitors' "pixel" size ethos would have ticked plenty of boxes. But with physical sensor size comes physical device size, and the HTC One, unlike the Nokia 808 PureView, is a trim, delicate slice of smartphone.
As a camera replacement
Using the HTC One as a camera doesn't feel much like a camera. Without wanting to sound too "duuh" it's obviously a smartphone - that's the way it's been designed and that's the right way to approach such a device.
But if HTC had included a physical exterior shutter button we think holding the device steady would have been made easier - as it stands the overall thinness of the product doesn't lend itself well to keeping a decent grip with one hand, and you sure wouldn't want to drop this pricey kit.
READ: HTC One review
The touchscreen - which can be used to position the focus point and, in doing so, the metering - is incredibly responsive and the large size makes for a glorious preview which, in many respects, walks all over standalone compact cameras. This is how the camera menus are controlled, however, so you'll need one hand to hold the product and the other to tap the screen for focus, shutter and other more detailed controls. But the layout and depth of controls don't lend well to dedicated camera use.
Controls aside, among the biggest problems we had with the One is that it tends to expose for highlights which can cause silhouetted shots in all kinds of situations and the flash isn't anywhere near bright enough to counter that in daylight. It's a problem that can be addressed partially by the +/-2EV exposure compensation - if, that is, it wasn't buried in the unnamed "…" menu and required scrolling down to it on each visit.
The fact such controls - including ISO sensitivity, white balance, sharpness and more - are included is a great thing, but then full manual controls are omitted. Not necessarily the clincher in buying a camera or a smartphone by any means, but aperture priority, shutter priority and full manual controls would each have their own clear uses, even if they were dressed up into more consumer-accessible "portrait", "sport/fast action" and other scene mode options.
There are notable benefits to using a device such as the One which has a speedy processor at its core. The One can snap away shots at a rapid rate, with the likes of Best Shot's auto-select method or Zoe's three second mini-movie capture (which can be used to extract stills from later) each being of great use for casual capture. We like.
Above all else it's about the pictures. The One's resulting images are okay at best - among plenty of problems there are some high points too.
It's the improvement to signal-to-noise ratio that the sensor's larger pixels brings to the table and so, at higher ISO settings, the One's shots are cleaner than near rivals such as the iPhone 5. That's without a doubt.
But the One does its damnedest to avoid using the high ISO settings most of the time. Instead it'll happily snap - sometimes unhappily for the resulting images - at 1/20th second at, say, ISO 200 instead of 1/40th second at ISO 400, for example. We can see why, it's because the lower ISO settings are so much more preferable. Rise to ISO 300 and above and image noise in shadow areas is clearly visible.
Then it's back to the resolution conundrum again: scale a competitor's shots down to 3 or 4 megapixels rather than 12 megapixels and it helps "hide" some imperfections. Snap a four-figure ISO shot with the HTC One and it'll definitely show up less image noise compared to its major rivals - but there's not enough detail to substantiate its worth as a "better" image. In short: the benefits are marginal because resolution isn't high enough.
Even at the lower sensitivities we found ISO 100 shots to present some sloppy processing: jagged edges in blown-out highlights, processing artefacts comparable to a compact camera of a greater resolution, colour fringes - those overlapping purple edges you may have seen in images at full size before - and a lack of biting sharpness from the lens combine a series of negatives that can't be ignored. As we've mentioned before it's exposure that's the One's most obvious downfall, plus the exterior lens often comes in contact with the hand which means it gets greasy and dirtied all the time and further softens images - you'll need to keep it clean and clear for the best results.
On the HTC's 4.7-inch screen any imperfections - exposure aside - are not as distinguishable as at full size on a computer monitor, and herein lies an argument that rests in HTC's favour: most users will just use images at small scale, often just on the smartphone itself, where larger resolutions aren't going to have much of an impact. Indeed a lot of users may not care less whether their smartphone camera is high resolution, they might not even know - so long as it can shoot in low-light conditions and deliver good enough results. The One does have that point wrapped up, or at least it does for its 4.7-inch display.
There are other fun elements within the interface too: the inclusion of filters means Instagram-like exposures can be made in black and white, negative, pop-colour, vignette and all manner of other options. Not great for everything, but impactful nonetheless, and post-shooting adjustments and edits can be made too.
Close-up or "macro" shooting is also very impressive. Slip the camera right up to a subject and it has no problem snapping in focus from just a couple of centimetres away. That's a benefit of a small sensor and lens combination right there.
The One major benefit
Okay, so there's more than one benefit to using the One as a camera, but that play on words was too much to miss out on. The thing that makes the HTC One camera great is its connectivity.
It almost goes without saying that a smartphone is most people's hub to the world; their portal to sharing and consuming news, pictures and the like. So when it comes to outing pictures from the One to the internet there are plenty of options. Mail it, Facebook it, tweet it - the world is your oyster. It's immediate, it's easy and it's this kind of feature that cameras are slowly trying to compete with. Try as they might, none is capable - short of the Samsung Galaxy Camera - of competing with that immediate and easy sharing capability.
READ: Samsung Galaxy Camera review
We've already touched upon Zoe too which, despite its girly name is short for zoetrope - a device which produces the illusion of motion from a series of still frames. The One is obviously far more advanced than such ageing tech, but Zoe and its associated galleries have a big impact on the way pictures can be stored and viewed. The mini-movie Zoe clips play back in a flick-book-like fashion in the gallery section for added impact, and the ability to open and edit photographs all from the phone is something most cameras aren't anywhere near to doing as yet.
Battery life, too, lasts for plenty of time. There's no popping spare batteries in either - it's simple USB-to-device pairing and, bosh, you're ready to go.
It's all this smartphone wizardry that sets the One apart from a camera and that's something that can't be overlooked. But then other smartphones offer the majority of such benefits too.
The HTC One is a great device on the whole that we're very fond of, but try to think of it as a dedicated camera and is it better than one? No, not at all.
Poorly measured exposure, so-so quality, limited resolution and a digital zoom you'll want to avoid are just some of the shortcomings. And while high ISO shots might well outshine their smartphone peers in terms of revealing less image noise, the limits of the One's resolution do, to some degree, knock itself out with one "ultra" blow which counters much of that low-noise benefit.
Marketing is a clever tool, but in this instance it's hype. The HTC One's camera isn't as ultra as its name suggests by any means. What makes it cool is the ability to apply filters, share direct from the device wherever you are, use Zoe and burst shooting, arrange galleries, and shoot for a long time. It's the smartphone's connectivity elements that make the camera viable - and while it's far from a camera-beater we suspect many owners will be happy with what it can do.
Great smartphone? Yes, about as good as they get. Great camera? 'Fraid not.