Overall Performance

The NEX-7 is overall a fast, responsive camera - it very rarely leaves you waiting during normal operation. In almost all regards - for example power on, menu operations and settings changes, shot-to-shot times, and browsing through images in playback - the NEX-7 is pleasantly fast (as you'd hope for a camera of its price). Indeed its continuous shooting performance is class-leading amongst the enthusiast-orientated mirrorless brigade, as it's capable of shooting at full resolution at 10 frames per second, or 3.7 fps while maintaining a live view feed. However, like other cameras that rely on contrast-detection autofocus, it doesn't have continuous AF performance to match.

Continuous Shooting and Buffering

The NEX-7 has two continuous drive modes, labelled 'Continuous Shooting' and 'Speed Priority Continuous'. The latter runs at a headline-grabbing 10 frames per second, although with focus fixed at the start of a burst and no live view feed. Meanwhile 'Continuous' runs at highly respectable speeds (reaching a maximum of 3.7fps if you fix focus manually) while still providing live view between frames - the fluidity of which is greatly improved by using the electronic front curtain shutter. The NEX-7 buffers sensibly during continuous shooting too, so unless you're in the habit of firing off complete bursts at 10fps, you rarely have to worry about the camera locking up. Once the buffer is full the camera drops to a slower, sustainable shooting rate; as this is defined by write speeds, it's faster if you shoot JPEG or use a fast card. The NEX-7's continuous shooting performance is summarized in the tables below, using a Sandisk Extreme Pro 8GB UHS-I SDHC card, Electronic First Curtain Shutter, and Manual Focus. Overall this is broadly similar to Sony's SLT-A65 (and therefore not quite up with the A77).

Continuous Shooting

JPEG Large/Fine
Frame rate 3.7 fps 3.7 fps 3.7 fps
Number of frames 24 16 14
Buffer full rate 1.6 fps 0.7 fps 0.6 fps
Write complete 11 sec 21 sec 24 sec

Speed Priority Continuous

JPEG Large/Fine
Frame rate 10.0 fps 10.0 fps 10.0 fps
Number of frames 16 14 13
Buffer full rate 1.7 fps 0.6 fps 0.6 fps
Write complete 11 sec 20 sec 24 sec

This is impressive performance by any standards - it surpasses almost any other mirrorless interchangeable-lens camera by quite some margin. The only exceptions are the Nikon 1 twins, the J1 and V1, which due to some clever sensor technology can shoot at 10fps with continuous autofocus. But with their smaller sensors and very different design philosophy, these cameras are likely to appeal to a very different audience - compared to immediate peers, such as the Olympus E-P3 and Panasonic DMC-GX1, the NEX-7 stands apart.

1 2 3 4 5 6 7 8 9 10
The NEX-7 can shoot at 10 frames per second, although with focus and exposure locked

Autofocus speed / accuracy

With static subjects, the NEX-7's autofocus is generally fast and accurate. It's not as blisteringly quick as the latest Micro Four Thirds cameras such as the Olympus PEN E-P3 and Panasonic Lumix DMC-GX1, but on the whole it's fast enough - there aren't many subjects that won't wait that extra fraction of a second for the camera to focus. Also, while it may be slower than many similarly-priced SLR/lens combinations, it's essentially immune from the front- and back-focusing problems that can affect the phase detection AF systems of SLRs.

The NEX-7 also improves its AF response times by checking focus during live view every couple of seconds and refocusing when it considers necessary, so that whatever is covered by the active AF point is normally pre-focused. Once you half-press the shutter, focus becomes locked. This is very similar to Panasonic's 'Quick AF' setting, except that it cannot be turned off. In normal use you're unlikely to even notice this is happening, let alone find it disturbing; it just has the effect of making AF seem faster. But if you really don't like it, your only real option is to set the camera to manual focus and use the AF/MF button to activate autofocus (by setting the AF/MF button's function to 'hold' in the Setup menu).

One weak point of the NEX-7's AF system is when used indoors under artificial lighting, which tends to present a tricky combination of low light and relatively low contrast. At this point focus speed drops right down, and when the AF illuminator is turned on the camera has a tendency to fall back on its 'large green rectangle' mode - in essence analyzing almost all of the frame to acquire focus. The problem here, aside from speed, is accuracy - the camera often chooses to focus on the background, so you may well need several attempts to get correct focus.

If you turn the AF illuminator off, the NEX-7's low light focusing is actually much better-behaved, and the camera is happy to focus on a defined AF point. However focus speed still isn't up there with the best in class (although this is probably as much to do with the lenses as the camera itself). In our assessment the NEX-7 is overall outperformed by current Micro four Thirds cameras in this respect, even when using a fast lens like the Carl Zeiss 24mm F1.8 - however it's probably still a bit better than the Fujifilm X100.

Like all other cameras that rely solely on contrast-detection AF, though, the NEX-7 is nowhere near as good at continuous and predictive autofocus. Whereas phase detection AF systems can determine from a single measurement how far to move the lens and in which direction to achieve focus, contrast-detect systems have to search through multiple focus positions to identify the correct one, which becomes problematic when the subject is a moving target anyway. What this means is that the NEX-7's C-AF mode isn't as effective as that on DSLRs or Sony's SLTs - although it's not obviously worse than most other mirrorless cameras.

Battery life

The NEX-7 uses the same NP-FW50 battery pack as the other NEX models, which has a 7.3 Wh capacity. Sony suggests you should get 430 shots per charge using the LCD, and 350 with the EVF - we're not sure you'll necessarily get that many in practice, but 300 shots should be achievable and we wouldn't describe the battery life as problematic. However recharging does take some time - about three hours from depleted to fully-charged - so it's certainly worth having a spare or two if you're likely to be shooting with the camera a lot.