Sigma DP1 review: Sigma DP1

The DP1 is the companion camera to Sigma's SD14. It uses the same unique three-layer Foveon sensor, but this time in a compact body with a fixed focal-length 28mm equivalent lens. It's designed for photographers looking for simplicity, clarity and quality rather than technological gimmicks. It's available now for around £500.

7.5

Sigma DP1

The Good

Simplicity of design; Foveon image quality; excellent Sigma PhotoPro software.

The Bad

Slow autofocus; slow image processing; breathtaking price.

The Bottom Line

The DP1 is about as far from the mainstream as you can get. It has some obvious limitations and some rather less obvious operational flaws but, despite this, the images produced by its Foveon sensor are of such a quality that you're willing to forgive an awful lot

Positives
Conventional sensors record colour data using a single layer of photosites covered by a mosaic of red, green and blue filters. The colour data for each pixel than has to be interpolated using data from its neighbours. The result is a loss of definition and clarity at a pixel level.

But the DP1's Foveon sensor has three layers, one each for the red, green and blue data. No interpolation ('demosaicing') is required, and at 100 per cent magnification, when other digital images have lost their edge, the DP1's show an amazing clarity and definition. Yes, its images do have only 4.7 million pixels, but they are of such a quality that you can print them much larger than those from a conventional camera.

The 28mm lens is another factor. Fixed focal-length lenses require far fewer optical compromises than zooms, and the result is images with distortion and fringing levels so low that you have trouble finding any. Not only that, the Sigma's images are sharp from the centre right to the edges.

The design is smart, elegant and simple. There are no frills and no gimmicks. It offers the usual program AE, aperture-priority, shutter-priority and manual modes that photo experts demand, and its autofocus system is backed up by a clear and simple manual focus dial.

As well as shooting JPEGs, the DP1 can also shoot raw files, which are processed using the bundled Sigma PhotoPro software, an excellent application that can draw the very best from the DP1's sensor.

Negatives
The DP1 does have flaws, however, and while some are obvious, some are not. The 28mm equivalent lens is the most obvious limitation. This might be fine for shoot-from-the-hip reportage photography and perhaps landscapes and travel shots, but not much else. Straight away, this makes the DP1 a fairly specialised kind of tool.

But there's worse to come. The autofocus is just too slow. You're likely to choose a camera like the DP1 for shots that depend on spontaneity and fast reactions, but it's just not quick enough. The solution is to revert to a classic film camera technique -- manual 'zone' focussing and a small lens aperture that ensures everything from a couple of metres away to infinity will come out sharp.

But that won't solve the Sigma's biggest problem -- its painfully slow image processing. It takes about two seconds to save even a JPEG file, and twice that for raw files. It can shoot up to three frames in a row, but then you have to wait many seconds while it clears the buffer.

It's not the Foveon sensor's apparently limited resolution that threatens to scupper the DP1, or even the limitations of the fixed focal-length lens, but the slow responses of the camera itself.

Conclusion
Never mind the megapixels. The DP1's images have a clarity and a quality that conventional sensors can't match, so it punches well above its apparent weight. The fixed focal-length lens isn't a problem, either, for those who long for a return to simpler cameras. The DP1's real weakness, though is its operational speed. It's simply too slow.

Edited by Nick Hide