The NEX-7's little built-in flash has a guide number of 6 (m, ISO100) which isn't exactly powerful, but still capable of reasonable range even with the kit zoom if you turn the ISO up a bit. Like the pop-up mechanisms on several other cameras of this type, you can pull the flash back and bounce it off a (low) ceiling for more flattering lighting, although you'll generally need to use high ISOs (1600 or more) to get a good exposure - and as this is distinctly an unadvertised 'feature', doing so is very much at your own risk.

If you use the flash often, you'll probably find that the NEX-7's default control setup infuriating - you have to dive into the menu to change flash mode or flash exposure compensation - and it makes sense to assign one or both of these functions to the soft keys. Unfortunately the NEX-7's built-in flash can't be used as a controller for off-camera wireless flash - a disappointing omission from such an expensive camera.

The NEX-7's small built-in flash does a decent enough job, with well-judged exposure. Its slightly offset position relative to the lens does however mean that you can get fairly obvious shadowing to the left of your subject, as seen here.

JPEG Sharpness settings

The NEX-7 uses much the same approach to JPEG processing as we've seen from previous Sonys, which means a certain emphasis on smoothing away noise at the expense of fine, low contrast detail such as grass or hair. The upshot of this is that, just as we noted in our SLT-A77 review, the camera's JPEG output doesn't really show the full extent of the detail that can be captured by that 24MP sensor.

If you want to get the most detail out of the camera's JPEGs, then it's worth experimenting a little with the sharpening setting - turning this up to +1 or +2 can enhance the appearance of detail, although we'd probably steer clear of +3, which can show very obvious halo artefacts. However if you want to extract all of the detail that the sensor has captured, you'll still need to shoot RAW.

Naturally this all has to be placed in context - with the sheer size of the NEX-7's image files it only really matters if you normally view your images at 100% on-screen, print extremely large, or crop aggressively before printing.

The 100% crops below show the effect of the JPEG sharpness setting on both halos around high-contrast edges (which become more pronounced as sharpness is increased), and low-contrast detail. As is often the case, careful sharpening of a RAW file generally yields the best results.

(ISO 100, E 18-55mm F3.5-5.6 OSS, 55mm F8)
JPEG, Sharpening = 0 (default)
JPEG, Sharpening +1
JPEG, Sharpening +2
JPEG, Sharpening +3

Shadow Noise

The Sony NEX-7 uses a newly developed 24MP CMOS sensor, shared with the SLT-A65 and SLT-A77. This follows on from the last-generation 16MP sensor which has impressed us greatly in the original SLT-A55, the NEX-5N and NEX-C3, and the Nikon D7000. A characteristic of these sensors is a low noise floor at low ISOs, which means you can lift shadow areas without running into objectionable noise levels.

The examples below compare the NEX-7 with the SLT-A77 and two enthusiast APS-C SLRs, the Canon EOS 7D and the Nikon D7000. The NEX-7 performs visibly better than the SLT-A77, due to the latter's light-sapping 'translucent' mirror. The Nikon D7000 (and by extension, other cameras such as the NEX-5N which share the same sensor) does a bit better at the pixel level, but for many uses this will be offset to a degree by the NEX-7's higher pixel count. Meanwhile the Canon EOS 7D lags somewhat behind in this particular comparison.

Sony NEX-7 - ACR+3.0EV (ACR NR: 0) Sony SLT-A77 - ACR+3.0EV (ACR NR: 0)
Nikon D7000 - ACR+3.0EV (ACR NR: 0) Canon EOS 7D - ACR+3.0EV (ACR NR: 0)
Sony NEX-7 - ACR+3.0EV (ACR NR: 0) - 100% crops
Sony SLT-A77 - ACR+3.0EV (ACR NR: 0) - 100% crops
Nikon D7000 - ACR+3.0EV (ACR NR: 0) - 100% crops
Canon EOS 7D - ACR+3.0EV (ACR NR: 0) - 100% crops

This might seem like extreme pixel-peeping of little practical consequence, but there are real-world photographic ramifications. If you shoot RAW it means that you can draw more detail from the shadow areas of the NEX-7's files than you might expect, without a huge noise penalty (remember the images above were converted from RAW files with Adobe Camera Raw NR turned off). If you shoot JPEGs, then you can take advantage of Sony's Dynamic Range Optimization (DRO) function confident that you won't give shadow noise an unpleasant boost.

Overall image quality

The NEX-7's overall image quality is, on the whole, remarkably good. Indeed we'd go so far as to say that at its best it surpasses any other current APS-C camera, bar none. The 24MP sensor is capable of resolving immense amounts of detail (just as long as your lens is up to it), but at the same time its high ISO performance is a match for pretty well any APS-C SLR. The NEX-7 may be an expensive camera, but you'll need to spend a lot more money to get hold of a substantially better sensor.

Just as important, metering and exposure are generally accurate, and tend to err on the side of protecting highlights (which definitely counts as a good thing). The camera also offers the user enough cues to avoid exposure errors on those odd occasions when the metering has been fooled, with full-time exposure simulation and a live histogram that, while small, is a pretty good predictor of the final output. If you shoot JPEGs you can turn on Auto DRO and generally trust the camera to come up with a balanced image, holding highlight detail and boosting the shadows in a visually realistic fashion without excessive noise.

The NEX-7's auto white balance system on the whole does a decent job when left to its own devices, although it can often give too-cool renditions of subjects in shade. It's also reluctant to fully compensate for low colour temperature artificial light, often giving an unpleasantly strong orange cast (to be fair it's not alone in this regard). But again, one of the advantages of a fully-electronic finder system is that you can generally see very easily when it's getting things wrong, and compensate accordingly.

We have some reservations about Sony's JPEG processing, and its tendency to smooth away noise at the expense of detail even at low ISOs. The relatively-crude wide-radius sharpening also means that the finest low-contrast detail tends to be lost. With so many pixels to play with this can feel like nit-picking, but it's clear that there's a fair bit more detail in the RAW files than ends up in the JPEGs, no matter what you do with the Sharpness setting.

Perhaps the biggest question mark hanging over the NEX-7's image quality, though, is nothing to do with the sensor. Instead it's about how many of the native E-system lenses can provide sufficient cross-frame detail to make full use of all those pixels. The E 18-55mm F3.5-5.6 OSS kit zoom certainly struggles to keep up, giving visibly soft edges and corners at almost all settings. But again, this has to be placed in context - in terms of the overall detail captured, the NEX-7 will always match or exceed the NEX-5N when compared like-for-like. Overall though it's a camera that cries out for more top-quality native lenses than you can currently buy.