Image Quality and Performance 

Android 4.1 on the Xperia Z’s quad-core processor makes for a stable and speedy user experience. With 2GB of RAM, programs tend to stay open in the background for quick relaunch times, and with 16GB of onboard storage backed up by a microSD card slot, there’s plenty of room for whatever you want to cart around.

 For those who need more than the 16GB of internal memory the Sony Xperia Z offers a Micro-SD slot.

The camera app takes about two seconds to launch the first time you use it in a boot cycle, but thereafter opens more or less immediately. Shot-to-shot times of around a half second help give it a nimble feel.

Focus acquisition is reasonably fast, and the Z has a number of modes to pick from: single point, multi-point, face detection, touch focus and object tracking. They’re all useful except for object tracking, which keeps the focus reticule over a specified target with limited success. As in other modes, the Z doesn’t worry too much about actually holding a focus lock on anything until you press the shutter button. This means the focus delay is a part of the shutter lag nearly every time (though if you immediately shoot again, the Z seems to prioritize getting the next frame over refocusing). 

Focus accuracy is good in bright light and falls off in low light, as with most phones and cameras in general (frankly, in low light, minor focus errors are likely to be hidden by the blur of noise reduction anyway).

The Z rarely exhibits annoying “early shutter penalty.” If you re-press the shutter button before the camera is ready to fire again, the Z will (usually, at least) snap off another frame an instant later. We prefer this to the behavior of most phones, which completely ignore the shutter button until they’re ready to shoot again.

Daylight, Low ISO 

In good light, the Xperia Z produces well-exposed photos that look good at screen and web resolutions but look heavily processed at higher magnifications. 

Colors are pleasant and well-balanced in Normal mode. Blue skies and green foliage are rendered nicely without the eye-popping saturation boost that some phones insist on adding to images. If you do like your colors turned up to 11, Superior Auto mode tends towards heavier saturation. 

Areas without detail like skies look smooth and noise free at low ISOs thanks to aggressive noise reduction, but the flipside is that low-contrast detail is largely obliterated, even at the Z’s low base ISO of 40.

Pixel-peeping phone camera output is rarely rewarding, but the Z’s pixel-level image quality is below par even in good light. Besides the sacrifice of low-contrast detail (not an uncommon failing), the Z’s output suffers from an over-processed, water-colored look that puts it a distinct step behind the best of its competitors.  

For the most part, the Z’s lens isn’t a bottleneck in terms of image quality, though our review unit did have a very soft lower left corner with blurriness visible when viewing full-screen images on a 24-inch monitor.

The Xperia Z’s photos in good light are generally pleasing at web and screen resolutions, but aggressive noise reduction sandblasts a lot of low contrast detail out of images.
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Zooming in on the Z’s images reveals an over-processed look, most likely the results of overzealous noise reduction and sharpening
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The Z renders pleasant skin tones in good light. As with all phones with wide-angle lens, you have to get close to fill the frame with a head and shoulders portrait.
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The Z’s color rendition is pleasantly saturated without going over-over-top in Normal mode (shown here), though Superior Auto mode sometimes cranks up the saturation.
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As with all cameras with small sensors, the Z’s limited dynamic range leads to blown highlights in scenes with wide brightness ranges. The Z’s HDR mode provides some extra latitude in such situations, but since any subject movement creates ghosting artifacts it’s less useful for pictures of people.
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Low Light, High ISO

The Z can cope with the lights going down, but its low light performance lags the leaders. As the ISO climbs, image quality drops progressively with increasing mushiness giving way above ISO 800 to noise so exuberant that no amount of smoothing can cover it up. That said, the Z manages to deliver images that are totally usable at web resolutions under most lighting conditions in which people are likely to photograph.

In Normal mode with ISO on auto the Z will reach up to ISO 1250, 5 stops above its base ISO of 40. Both the “High sensitivity” scene mode and stabilizer function extend that to ISO 2500. The native camera app supports manual ISOs from 100 to 1600.  

The Xperia Z is surprisingly shy about cranking up the ISO when given the choice, probably because of the resulting drop in image quality. In Normal mode, the Z won’t hesitate to use exposures of 1/10 sec at ISO 400 or 1/8 sec at ISO 500. Those low shutter speeds are likely to cause blur unless you can hold the phone very steady; Sony would probably be better off just biting the bullet and upping ISO a bit. The stabilizer function goes a little too far the other way, pegging the shutter speed at a very hand-holdable 1/32 sec exposure even if it means that the resulting image crackles with noise. In theory you can set ISO manually, but since the Z (just like every other phone we’ve used) doesn’t report the shutter speed it’s using, you won’t really know when you need to goose the ISO higher.

The Z has an LED flash that does the trick for casual portraits in dim light but doesn’t work any miracles. It’s whiter than most artificial lighting so there’s usually a mismatch between the subject and anything else under ambient light. In addition to the usual on, off, and auto options, it has a fill-flash setting that’s mostly wishful thinking: the backlighting has to be pretty low for an LED to fill in the shadows.    

At ISO 250, this image looks good at web and screen resolutions, with noise remaining under control and colors staying accurate. However, looking closer reveals how much detail is already being blurred away.
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By ISO 400, more details are falling victim to noise and processing, but the image remains largely satisfying at web and screen resolutions.
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Here the Z has chosen ISO 800 and an easily blur-inducing shutter speed of 1/8 sec. The loss of detail is evident at screen resolution and may show in smaller web formats as well. Blue color splotchiness is visible at screen resolution.
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For this seriously low light scene, the Z underexposes a bit if left on auto ISO: its maximum normal exposure, ISO 1250, 1/8 sec, just isn’t enough. We manually set ISO to 1600 for this photo, which is still a little dark. This is a torture test, and the results are pretty tortured: detail has left the building and there’s lots of crunchy noise artifacts. That said, it could work in a pinch at web resolutions.
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The Z’s LED flash does a decent job with indoor portraits, though as usual it’s hard to match the white output of the flash with warmer incandescent lighting.
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