Sigma DP2x

Sigma DP cameras are in many ways the black sheep of the camera market. First of all, they're compact cameras but they have large-format sensors (usually found in SLRs)—a feature they only share with the Leica X1 and Fuji X100. Next, they don't do wishy-washy wide-angles, as they come with either a genuine 28 mm lens (DP1 and later) or a standard 41 mm lens (DP2 and later). Finally, in spite of their high-end status, these cameras take pictures in a resolution of 4.7 Megapixels!

The DP2x is the third version of the DP2, and one of the main aims of this updated model is to improve responsiveness, which is the real weakness of this range.

Handling

It's clear that Sigma doesn't play the style card when designing its cameras. The cameras look to have been thought up by a designer who got fired from Lada or Pilatus, before being hacked from a block of plastic using a miniature axe. Plus, along with Leica cameras, they're the last survivors of the film photography school of camera design, in that ISO sensitivity isn't considered to be a separate parameter, the only shooting modes available are PSAM and the video mode is something of an afterthought.

On the outside, the DP2x is identical to the DP2s—the camera bodies are the same down to the last little dot of the textured grip. The camera is exceptionally well made and feels sturdy and robust. However, it's still as smooth and slippery as ever, and the unusual controls still make handling feel rather strange (no mode-selection dial, menus spread over the OK, Menu, QS buttons and Setup mode, some settings you have to validate twice but others just once etc.).


The low-def LCD is really quite outdated (see inset), manual focusing is still as impractical as ever and the lens still makes the same less-than-reassuring noise. In other words, the camera's design and handling hasn't changed a bit.

Responsiveness

Just like when the DP2s was released, the DP2x claims to be faster than the previous model, with particular emphasis on the autofocus.

The DP2x certainly is faster than the DP2s, and not all manufacturers are able to gain a second on the focusing time and photo saving time between two generations of the same camera. In good light, the autofocus has been upped from sluggish to acceptable, even if other compacts still do a little better (regular compacts, micro four-thirds cameras and Sony's NEX cameras). Similarly, the time it takes to save a picture has been cut from incredibly annoying to just about OK, at a little under two seconds.

However, the camera's start-up time hasn't been improved, and at 4.6 seconds it's still way too slow. That's pretty unforgivable!

Picture Quality

The Foveon x3 sensor used in Sigma cameras can't really be judged using the same criteria as regular camera sensors. It takes pictures in 4.7 Megapixels, which seems completely ridiculous when the most basic of compact cameras shoot in 12 Megapixels these days, when many compacts now have 16-Megapixel sensors and when consumer SLRs are edging closer to 20 Megapixels.

What's unique about the Foveon sensor is that for each pixel, it captures the three basic colours of light (red, green, blue) separately, while standard 'Bayer filter' sensors only capture one colour per pixel. An algorithm is then used to 'recreate' the quantities of the other two colours based on the values recorded by nearby pixels. This is known as demosaicing—an operation that can create visual artefacts such as moiré. To keep these unwanted effects to a minimum, a 'low-pass filter' is used to deliberately blur the image a little. The number of Megapixels in Bayer filter cameras is therefore not, strictly speaking, a true resolution, as adjacent pixels can't represent radically different colours.

The Foveon sensor, on the other hand, doesn't need to do any demosaicing and doesn't have a low-pass filter. Each of its pixels is a genuine pixel that is completely independent of adjacent pixels.

That means that if the lens is up to scratch, the image should be 'perfect' for its resolution. Thankfully, the 41 mm f/2.8 lens used in DP2 cameras is really very good, giving very sharp results over the entire frame. On the test shot at 50 ISO, contour lines just one pixel thick would be blurred by demosaicing with a Bayer filter camera. Here though, they can be clearly distinguished and the components on the circuit board are razor sharp and minutely detailed.

The DP2x handles noise quite a bit better than the DP2s, and you can now use the 800 ISO setting without too much trouble ... just like in cameras that use BSI CMOS sensors, and which are often a fair bit cheaper!

Compared with large-format Bayer-filter sensors like those found in SLRs, micro four-thirds cameras or the Leica X1 and Fuji X100, however, the Sigma doesn't look quite so impressive, as these can push up to 3200 ISO without picture quality suffering too much.
 

The image processing system has been improved in several clearly noticeable ways. The white balance, for example, although still not perfect, no longer goes crazy under artificial light, as you can see in the Barbie Face-off shots for the DP2s and DP2x. That said, you're still better off using the manual white balance options or—even better—working in Raw mode, as the DP2x isn't a fan of indoor, artificial lighting.

Although the lack of stabilisation isn't too much of a problem with wide-angle lenses, it starts to become more noticeable in cameras with 'standard' lenses. Plus, performance at macro settings is quite simply awful compared with current market standards. That won't be a problem for all users—but just don't say you haven't been warned.

All in all, the DP2x deserves five stars for picture quality ... for certain specific users. For everyone else though, the sensitivity worthy of a compact-format sensor and the lack of stabilisation system limits its performance to three-star quality.

Video

Erm, 320 x 240 pixels? Is Sigma having a laugh?!


Sigma has every right to hate the idea of a video mode in a camera, but in that case, we'd rather the manufacturer not bother including one, like Leica did with the X1.