With its beautiful full-metal body and impressive spec-sheet the HTC One has been one of the highest-profile smartphone launches of 2013. The low-resolution 4 "ultrapixel sensor," fast F2.0 lens and optical image stabilization also make the new HTC flagship a very interesting option for mobile photographers.

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We are currently working on our review of the One and have already had a close look at its image quality in our recent Smartphone Super Shootout and our comparison to the iPhone 4S. To shorten the wait for the full review we thought we should give you a preview of the HTC's most interesting camera features. To top things off we have also added a comprehensive sample gallery containing 45 images. We are planning another article looking at the One's new Zoe movie feature within the next few days, so watch this space.

Exposure and HDR

On the HTC One's default camera app offers "traditional" exposure buried deep in the menu but by default exposure is linked to the focus point, very much like on Apple's iPhone. If you tap and focus on a bright part of your scene you'll get a darker exposure and the other way around. The samples below illustrate how this works, the green square indicates the focus/exposure point. For comparison purposes we have also included a shot taken in HDR mode.

For this shot we focused on the brightly lit white tarpaulin on the left boat. This gives you some detail on the fabric but overall the image is heavily underexposed.
Focusing on a shadow area such as the hull of the boat on the right gives you an overexposed image with large clipped highlight areas.
Tapping on a mid-tone area of the scene gets you the most balanced exposure. However, in this high-contrast situation we still end up with clipped highlights on the green boat's cover.
The HDR shot shows a bit more of both shadow and highlight detail than the shot above, but overall the effect is so subtle that we think the HDR mode on our review sample might be broken. HTC has issued a software update addressing this issue. We will re-shoot this test as soon as it is available for the U.S. version.

Sometimes you might have to tap a few different areas before you get the desired exposure but mostly this system works quite decently and makes sure your focus area is well exposed. However, the tap-exposure works best in scenes with balanced lighting. Capturing a high-key or low-key scene is next to impossible as you won't find a dark or bright enough area in those scenes to achieve your desired exposure. The only way around this is either using the exposure compensation function that is hidden in the "Image Adjustment" section of the menu or a third-party camera app that offers exposure compensation, such as Camera FV-5 or ProCapture.

This forest scene makes it difficult to find a focus/exposure point that is bright enough to trigger a dark enough exposure to convey the atmosphere of the scene. 
The only way to capture the dark mood of the scene and getting some highlight detail in the flowing water of the stream is by tapping on the small area of bright sky in the top left corner, even if that's not really where you want to put the focus. You'll have to dive deep into the menu to add negative exposure compensation.

Backlight mode

Like many compact cameras the HTC One offers a range of scene modes which can be accessed through the menu. On top of the usual landscape and portrait modes, which are largely contrast and saturation variations, you also get the more interesting Backlight mode. In high contrast scenes this mode lifts the shadow areas to create an image with less harsh contrast.

In the sample below you can see how in this contre-jour scene the dark shadows have been lifted. The effect is quite strong which results in a slightly unnatural look. When examining the 100% crops you can see that the Backlight mode also introduces shadow noise and a lot of noise reduction smearing which close up doesn't look pretty at all.

Standard mode
Backlight scene mode
 100% crop
 100% crop

When the luminance difference between highlight and shadow areas in a scene is too large the Backlight mode comes to its limits. We took the portrait below indoors in front of a window. Focusing on the subject's face in standard mode gets you a very dark subject and and an overexposed background. It appears the One's metering system is reluctant to totally blow out the background, even when the main subject is very dark.

Taking the same shot in Backlight mode slightly lifts the shadow while the background exposure is roughly the same as before. That said, this is still not exactly a great exposure and like in the sample above, the image is blighted by shadow noise and noise reduction artifacts.

Standard mode
Backlight mode

Panorama mode

Like many smartphones and digital cameras the HTC One offers a sweeping panorama mode. In landscape mode you can capture a full 360-degree panorama but unusually there is no option to capture panoramas in portrait orientation. On the plus side the stitching is very good, with very few visible stitching errors in our tests. The resulting panoramas are approximately 9500 pixels wide and just over 1000 pixels high.

Exposure is locked when the first frame is captured. So you need to make sure exposure on that first frame is roughly in line with the rest of the scene, otherwise you might end up with an over- or underexposed image.

Sweep Panorama mode allows you to capture a full 360 degree view.  Stitching quality is very decent.
In high contrast scenes exposure can become a little tricky but we managed to preserve some shadow detail in the building and kept highlight clipping within acceptable limits by initially setting the focus point on a medium-bright part of the scene.
It took us a few attempts to achieve a decent exposure in this darkish overcast scene, but again the stitching is very good.
This is the same location as above but we initiated the panorama in a dark part of the scene which resulted in overexposure of the remaining frames.

HDR video

The HTC One is one of the first smartphones to offer HDR video in Full-HD 1080p resolution (the Sony Xperia Z is the other device we are currently aware of to offer this feature). The One does the same thing in video mode as it does in stills HDR mode and combines various exposures for each video frame into one. We have also noticed that the image is cropped compared to the standard video footage. This is presumably to counteract any camera movement during HDR capture. We will confirm the exact mode of operation with HTC for our full review.

Below you can see a sample video of a high-contrast scene that was captured in the woods with the HTC One on a tripod. The trees in the shadow are very dark and at the same time highlights have clipped in the top left corner of the frame and, to a degree, also on the flowing water.

This is the same scene captured in HDR mode. As you can see the the shadow areas have been lifted and the highlight clipping signficantly reduced, with better detail on the flowing water. However, if you watch these videos at full-screen resolution the downsides to the HDR treatment become obvious. Despite the shadow areas being brighter they show visibly less detail than the standard version. Noise reduction is much heavier than in standard mode and blurs away most fine detail in the low-contrast foliage areas of the scene.

The frame is quite heavily cropped and then resampled to 1080p size which arguably contributes to the reduction in image detail. The illustration below shows the difference in framing. The large image shows the area captured in standard video mode. The green rectangular marks the framing of the HDR mode.

Slow motion video

Like some other recent smartphones the HTC One is capable of recording slow motion video. Footage is captured at approximately 4x speed which means 10 seconds of real-life action, when played back at the standard 30 frames per second, will turn into a 40 sec slow motion video. The video size is reduced to 768 x 432 pixels and no sound is recorded. When playing slow motion videos back in the phone's gallery app you can adjust the playback speed between original and 1/4 speed.

Summary

With the One's ultrapixel concept HTC is putting a lot of focus on smartphone image quality but the new flagship device also comes with a comprehensive imaging feature set. That said, most of the functions and modes we've had a closer look at in this article appear a little half-baked at this early stage in the product life-cycle. HTC has already released an update to address the HDR function, but unfortunately this patch is not available yet for our U.S. version of the One. We would expect more updates to be released in the nearer future.

The Backlight mode doesn't work particularly well in a contre-jour portrait situation which arguably is the most useful application for this type of feature and the shadow-lifting also introduces a multitude of nasty artifacts to the image. The panorama mode works well but it's unusual to not offer an option for capturing panoramas in portrait orientation. On most other recent phones we have tested this can be done to generate a less wide but taller panorama than in landscape orientation. HDR video is impressive in so far that it's a brand new feature not many competitors can offer. However, you pay for the increased dynamic range in your footage with a heavily cropped frame and visibly reduced image quality.

The exposure system is to a a degree a love-it-or-hate-it affair. It's very simple (which presumably is why Apple has been using a similar system on the iPhone for a long time) and works well in most situations but doesn't give you the flexibility to capture low- or high-key scenes unless you are happy to dive deep into the camera menu. If you want real control over your exposure you're much better off with a third-party camera app. As we mentioned above we'll cover the new Zoe movies feature in a separate article and we will continue testing all these features for our full review. If you would like to get a better idea of the HTC One's image quality please check our Smartphone Super Shootout in the meantime.

Sample Gallery

There are 45 images in our HTC One samples gallery. Please do not reproduce any of these images on a website or any newsletter / magazine without prior permission (see our copyright page). We make the originals available for private users to download to their own machines for personal examination or printing (in conjunction with this review), we do so in good faith, please don't abuse it.

Unless otherwise noted images taken with no particular settings at full resolution.