If the W70 has one stand-out feature, it’s battery life. It is powered by a Sony NP-BG1 Lithium-ion battery which is rated, in typical Sony we’ll-do-it-our-own-way style, at 3.4Wh. Everyone else in the entire world rates rechargeable batteries in milliamp-hours, or mAh, but not Sony. Sony has to be different, so it rates its batteries in Watt-hours.
From what little I remember of A-level physics, Amps = Watts/Volts, so the W70’s 3.6V battery is roughly 940mAh which is tiny by modern standards, but nonetheless it is able to power the camera for a claimed 360 shots or 180mins of playback. I took well over 300 shots on a single charge with a new battery, so this claim seems to hold water.
So far the W70 is about average in most respects, with a couple of good points, so naturally there are a couple of bad points to balance them out. Unfortunately the bad points are in the crucial area of image quality, which is odd because this is usually a strong point for Sony.
The main culprit is, surprisingly, the lens. Despite the assurance of the prestigious Carl Zeiss name, it suffers from very bad distortion, some barrel distortion at the wide end as is usually the case, but also severe pincushion distortion at the telephoto end, something I don’t think I’ve seen before on a digital compact. This effect is the opposite of barrel distortion, as you’ll see in the sample photos. At the telephoto end it also suffers from very bad corner blurring, but only at focusing distances of less than a metre.
As well as this the W70 also suffers from image noise. At 100 ISO the pictures are clean and sharp, but at 200 ISO and over there is visible image noise, getting steadily worse up to the maximum 1000 ISO. It’s not the worst I’ve seen, but it is annoying, because other than these flaws the image quality is very good. Exposure, dynamic range and colour reproduction are all first class, focusing is accurate and apart from the close-range telephoto shots edge-to-edge sharpness is excellent. It’s just a shame it’s not consistent.
The Sony DSC-W70 is pretty much the definition of an average snapshot compact. It is well made, looks good, is reasonably light and compact, performs competently and can take decent pictures. It has a couple of strong points, namely its excellent low-light performance and exceptional battery life, but it also has a couple of flaws, specifically image noise above 200 ISO, and that unusual telephoto lens distortion. Good value for money, but doesn’t stand out in a crowded and competitive field.