Overall handling and operation
The user interface of the NEX cameras was always going to have to be innovative, given how few buttons there are. And it certainly is that - it's an interface that has more in common with consumer electronic devices than traditional cameras, which makes sense given that Sony is trying to attract people without in-depth conventional photographic knowledge. With the advert of firmware 03, it's greatly improved (we cannot stress enough the value of ensuring your NEX is running at least version 03).
Specific handling issues
iAuto mode in generally very good - you can just point the cameras at a subject and shoot. Our real disappointments are the inability to adjust image brightness (exposure compensation), and that it does nothing to encourage you to learn about what it's doing. Something as small as highlighting the aperture value when you adjust the 'defocus background' option would at least hint at what parameter was being changed.
Sony could have made NEX one of the easiest ways of learning how to use PASM modes simply by making iAuto's Bkground Defocus function and Aperture Priority modes (which are, in principle, doing the same things) use the same buttons to engage and confirm the aperture setting. It's not a fault with iAuto mode but it's a huge missed opportunity (and one that many manufacturers overlook).
We're also concerned that the 'Bkground defocus' mode is simplistic to the point of being misleading. When presented with a scale running from 'Defocus' to 'Crisp,' most people will push the setting all the way to 'Crisp' if they want in-focus backgrounds and yet doing so will push the camera to tiny apertures between F22 and F32 that will make their images softer (because of diffraction), less detailed (because of the high ISO settings and accompanying noise reduction needed for working at such small apertures), and more likely to be shaken.
There's a similar problem at the 'Defocus' end of the scale: if you use the kit zoom lens, then part of the 'defocus' end of the scale becomes unavailable as you zoom-in (because the long end of the zoom has a maximum aperture of only F5.6, not the F3.5 at the wide end). This clearly suggests less ability to defocus the background, but in practice 55mm F5.6 will give much more defocused backgrounds than 18mm F3.5 (because the level of background blur is dependant upon focal length as well as F-number).
Despite the cameras' point-and-shoot ethos, the PASM modes are where they really begin to shine. Regardless of the small number of external buttons, the interface has been improved with firmware 03 so that most key shooting settings are easily accessible.
The first thing we would suggest doing upon buying a NEX is visiting the setup menu and editing the 'Soft Key Settings' options - simply putting ISO access onto either the central or lower button makes PASM mode a much more pleasurable experience. The menu system is a little easy to get lost in but you rarely have to venture into it while shooting, so it's not a problem.
Manual focus assist, the magnified live view that is pretty much essential for anyone hoping to use non-E-mount lenses, can be assigned to the lower button for easy access. With firmware 03, it jumps back to the last used point on the screen, which is really useful if you're trying to focus on the eye of a subject for portraiture, for instance.
Sadly there's still no way to lock focus or exposure except by a half-press of the shutter button, so you can't separate the two. This makes it awkward to focus and recompose (as you have to meter at the point you focus), which you may find you want to do with subjects moving faster than the autofocus can cope with.
The NEX is a generally responsive camera with occasional delays into the shooting process. The startup time is around 1.2 seconds, making it a fraction faster than the Olympus E-PL1 but a little slower than Panasonic's GF1. It's certainly not likely to be a problem.
There's a more noticeable delay if you attempt to take a second photo, introduced by 'auto review,' the post-shot image review option. When this feature is turned on, you regularly have to wait between 2 and 2.5 seconds before the camera will shoot again (releasing the shutter button, half pressing to dismiss the review image and then full pressing again can get the shot-to-shot time down to 1.6 seconds but it's hard to achieve consistently). The situation is improved slightly in continuous shooting mode, with the preview image appearing more quickly but, if you don't try to shoot immediately, you can still have to wait until the camera feels like responding.
The other option is to turn the review option off, which brings shot-to-shot times down to a much more impressive 0.7 seconds. However, image review is a near-universal feature that many camera users expect (we were asked 'how do I see the image I've just taken?' by more than one compact camera user), and slows the camera down to a greater extent than we're used to seeing. We consider having to turn it off to increase responsiveness be a work-around, rather than a simple solution to the problem.
Continuous Shooting and buffering
The NEXs have two continuous shooting modes: a rather unimpressive conventional mode offering 2.3 frames per second (though considering the extent to which all mirrorless cameras struggle with continuous autofocus, it doesn't work out significantly slower than these peers), and a much more handy 7 frame per second 'speed-priority' mode that doesn't attempt to refocus between shots. This latter mode can be really useful if you're shooting subjects that exhibit predictable movement that can be pre-focused for. This rules out fast-moving kids and many sports, though.
After a burst of shots, it's not uncommon for the camera to slow right down until it's finished writing to the card - it'll let you enter playback mode but can stick unresponsivley on some images until it's finished writing.
In continuous mode (Identical results from NEX-3 with Lexar Memory Stick and NEX-5 with Sandisk Extreme III SDHC card):
- JPEG (Fine): around 2.5fps for 35 frames, then around 1.4fps
- RAW: around 2.5fps for 8 frames then around 0.6fps
- RAW + JPEG: around 2.5fps for 7 frames then about 0.5fps
- Recovery time: around 9-12 seconds
In performance terms, the basis on which mirroless cameras currently stand and fall is their autofocus speed - the underlying image pipelines tend to come directly from existing DSLR cameras and hence have been fairly well worked out, it's the focus lag that causes problems.
The NEX does pretty well in this respect. It's perhaps not quite as rapid as Panasonic's Micro Four Thirds cameras but it's very unusual for there to be enough of a delay that it becomes noticeable. In very low light, the AF slows down by a fair degree, even if the subject is within range of its autofocus illuminator.
In common with some other contrast detection AF cameras, the camera can sometime struggle if there's a dramatic change in focusing distance between shots. Presumably in the name of speed, the camera will initially search for focus around the distance it had last used (rather than scanning through the lenses entire range, which would slow things down considerably), which means that it can lock focus on the background when you're trying to shoot a close-up, and resolutely refuse to change. It's not a problem you'll encounter regularly, though.
The manual AF point selection mode is one of the better aspects of the camera's interface, with the bottom button giving immediate access to AF point movement, making it quick and easy. And, unlike the rather unhelpful live view magnification, it retains the previously used position until you change it.
Continuous AF can also be a weak point for cameras based on contrast-detection autofocus because they cannot know which direction they need to move the lens, and instead have to scan on either side of the previously focused point. The NEX is much like the competition in this regard - you can't expect it to keep up with unpredictably-moving subjects such as small children.
Although the battery life of both the 3 and 5 are rated at a totally respectable 330 shots, based on CIPA testing, the real-world experience is often not nearly as good as this might lead you to believe (a conventional DSLR quoting the same figure is likely to last much longer, as the screen is used much less frequently, unless you constantly use live view).
Presumably because of the large, high-resolution screen, the NEXs can chew through battery at a terrific rate. The NP-FW50 battery itself is rated at 7.3Wh, which is not at all bad for its size (the larger battery in the Olympus PEN range offers 8.3Wh), we'd strongly suggest buying a spare - if you're a ken shooter it's it's easy enough to burn through one in a day's shooting.
The really helpful battery percentage charge indicator keep you aware of how much battery you've used (and how little you've got left), and needs to have an eye kept on it. For weekend trips, many users may find themselves having to include the battery charger when working out how small they can pack a NEX system.