The NEX-5's overall performance is very impressive, and is on a par with a good mid-range DSLR. It starts up and is ready to shoot in under a second, and in single-shot mode it can maintain a shot-to-shot time of approximately 0.9 seconds in both JPEG and Raw plus JPEG modes. It has two continuous shooting modes, the first being a standard mode that includes autofocus between shots, which can maintain 2.5 shots per second, shooting until the memory card is full in JPEG mode, or for eight shots in Raw plus JPEG mode. The other is a speed priority mode which only focuses on the first shot, but which can manage an impressive 7fps in both JPEG mode (for approximately 20 shots) and Raw plus JPEG mode (for eight shots).
As you'll gather from those figures, the autofocus system is extremely fast, focusing in a fraction of a second in good light. It does slow down slightly in poor light, but even in total darkness it can focus in under a second, with a very bright AF assist lamp that has a range of several metres. One minor niggle is that the lamp is positioned in such a way that it is easily obscured by the knuckles when gripping the camera.
The NEX-5 uses an APS-C size sensor, the same as a full-size DSLR, so as you might expect the image quality is comparable to that of any of Sony's Alpha cameras. The lens is also of extremely high quality, with excellent detail and edge-to-edge sharpness with none of the chromatic aberration that bedevils some of Sony's cheaper Alpha system kit lenses. Colour rendition is superb, exposure is extremely accurate and reliable, and the level of fine detail is as good as any 14MP digital SLR on the market. In theory Raw mode should be even better, since it produces uncompressed files of nearly 15MPB, but unfortunately the supplied PMB conversion software appears to be unable to convert Raw files to anything larger than 1920 x 1080 resolution with severe JPEG compression, and the NEX Raw file format is not yet accommodated by Adobe Camera Raw.
One big advantage of the larger sensor format is reduced noise, and here the NEX-5 scores very highly. It has a minimum ISO setting of 200 ISO, and a maximum of an ultra-fast 12800 ISO. Shots at up to 800 ISO are effectively noise-free, and even 1600 and 3200 ISO produce very acceptable results. 6400 ISO does show some pretty severe noise reduction, with blotchy colour and reduced detail, and the maximum setting is quite noisy, but nevertheless it is a very impressive performance, especially when compared to its rival compact system cameras. The NEX-5 has the sort of image quality that really sets the benchmark for this class of camera.
The Sony NEX-5 is a very impressive debut into the compact system camera class. It is the smallest interchangeable lens camera on the market, but has outstanding build quality, plenty of useful features, excellent performance and the kind of still image and HD video quality you'd be lucky to get from a digital SLR. It really raises the stakes in the compact system camera market.