Labs

Digital SLRs

Testing digital cameras isn't quite like testing other types of hardware. The major aspects of choosing a printer, for instance - speed, running costs and print quality - are all easily quantifiable. Assessing a DSLR is unavoidably more subjective, so while we give the testing process a healthy dose of objective scoring, there's inevitably more scope for personal preference. Some, for instance, may like a camera body that's as small and portable as possible; others might find that same quality annoyingly fiddly. We try to take that into account as far as possible when we're testing.

The basic categories of assessment we use for every Labs don't change with DSLR testing, though. We still award each camera a mark out of six in four categories: Quality (in this case Image Quality), Features & Design, Value for Money and an Overall rating.

Image Quality

When we test digital compact cameras, we put an emphasis on the quality of the lens. With digital SLRs that can be contentious, since the lens can always be changed for a different model, and most SLRs can be bought body-only for a lot less cash. So we award each camera two overall quality scores: one Kit quality rating and one Body-only quality rating. The Kit quality is the overall image quality with the kit lens fitted to the camera, so taking effects such as geometric distortion and chromatic aberration - which are largely caused by the lens - into account. For the Body-only quality rating, we place more emphasis on image-quality aspects that reveal the abilities of the camera body itself, in particular the sensor's high-ISO performance, exposure-metering accuracy and dynamic range. Note that the Fujifilm S5 Pro isn't supplied in a kit with a lens, so it receives no score in the Kit quality test. Since noise performance is one of the main differentiators of DSLRs these days, we've teased that aspect out to give a High ISO quality rating, too.

Our DSLR tests also deviate from compact testing insofar as we adjust some settings manually to get a level playing field, rather than setting the cameras in fully automatic mode. For outdoor testing, for example, we put each camera in aperture-priority mode and take a shot at f/5.6 at ISO 100, at both the kits lens's maximum wide-angle and maximum zoom settings. Then, we take the same pair of shots at ISO 1600 to assess noise performance and look for signs of things such as clipped highlights, which indicate potential problems with sensor dynamic range.

Features & Design

The basic quality of all these cameras is relatively close, so features, build quality and overall ease of handling in everyday use are important. We award fixed numbers of points to each camera based on features such as the megapixel rating, number of focus points, maximum burst rate and extras such as a live-view mode. Some of these are more important than others: the number of megapixels a camera produces, for example, isn't necessarily correlated to its image quality, but a camera that can shoot at five frames per second has an undeniable advantage over one that can manage only three. The cumulative score for each category is thus weighted accordingly. Build quality is based on basic sturdiness of construction, with extra points awarded for features such as weather-sealed controls.

The Features & Design score also incorporates an element of the subjective feel and day-to-day ease of use of each camera: features such as whether the controls fall naturally under the fingers; the brightness and size of the viewfinder view; how easy and quick it is to change settings; and how often we need to resort to navigating the onscreen menu system to make an adjustment.

Value for Money

The Value for Money rating reflects a camera's score for Features & Design and Image Quality, in light of its price (including delivery). Top marks don't necessarily go to the cheapest camera, but rather to the one that delivers the best combination of features and image quality.

Overall

The Overall rating is a straightforward mean of each camera's scores for Image Quality, Features & Design and Value for Money, although due to rounding it may sometimes appear higher or lower than expected.