Sigma SD9

Every once in a while, a product really shakes things up. With respect to digital SLR cameras, there have already been a few milestones in recent years. Nikon's D1 broke through the quality and price barrier for many professional users, while the Contax N Digital gave us the first full-frame (35mm size) sensor. And with the SD9, we have a new name to add to the list, and from an unexpected source.

Sigma has been successful the world over for its independent range of lenses, which it produces for most major makes of camera. However, with its own SA mount, Sigma, in partnership with Foveon, has produced a new product utilising the X3 CMOS sensor, which combines three photo detectors layered on top of one another to measure red, green and blue light for each pixel. Foveon says the benefits include enhanced sharpness and, because there's no need for colour interpolation or colour filters, improved colour quality. Also, while the US technology company should be applauded for this development, so should Sigma itself, because the SD9 is no slouch as a camera either. However, the most amazing fact of all is that the SD9 retails for just £1,106. And although the physical sensor has just 3.54 million pixels, each pixel registers separate RGB information, giving a phenomenal 10.3-megapixel equivalent output quality.

The physical size of the sensor is only 13.8 x 20.7mm, which is quite small, but this has the upshot of increasing the effective focal length considerably. It's a classic case of the glass being half-full or empty - for sports, nature, travel, surveillance and close-up photography this is mostly beneficial, and the sensor has an inherent depth-of-field effect benefiting such uses. However, for those needing wide angles, it's potentially a drawback. We tested the camera with a 17-35mm f/2.8-4 EX lens (about £500).

But the innovative sensor isn't the sole unusual element in this camera, as it only shoots RAW image files. For many, the lack of native JPEG file support will be a disadvantage, although the 8MB RAW file does offer maximum quality. Sigma Photo Pro software is needed to turn the RAW files into JPEGs or uncompressed TIFF files. The latter will occupy 20MB of disk space saved as 16-bit images. While the software is commendably fast, it still takes time to process the image, and with a large number of photos it slows you down. So if you want quick photos or don't want to spend extra time post-processing, you should steer clear.

The good news is that the software is a good package, with not only extensive manipulation options for the RAW data, but pleasing browser capabilities and a good interface. Overall, it's actually far superior to the software provided with significantly more expensive cameras.

As this is a more affordable digital SLR, it lacks the ultra-robust metal shell seen on the likes of Nikon's D1x (see Reviews, issue 83, p157), but it still weighs in at 805g and manages not to feel cheap, although the finishing could be sleeker. The main command dial is placed around the shutter release, which is strange at first but easy to get to grips with. The menus and image-adjustment controls on the rear 1.8in display are easy to access too. During testing, we found the SD9 to be both quick and responsive.

The power section is less impressive, though, with four AA cells and two CR123A cells required for operation. Neither these nor the storage card (CompactFlash type I and II are supported) are supplied, but you do get a mains power unit. We were pleasantly surprised to see USB and FireWire connectivity, and both cables come bundled with the camera. There's no built-in pop-up flash, though, which seems an odd omission for what's essentially a general-purpose camera.