(Pocket-lint) - From the outset, the Sigma DP1 was going to be a headline grabber as it held out the promise of DSLR image quality in a pocketable package and all this from a relatively small camera manufacturer best known for it’s lens making.

It offers this possible photo nirvana to us based on Foveon’s rather controversial X3 CMOS sensor technology. For those not in the know, the Foveon X3 sensor differs from most sensor technology in that rather than having a Bayer colour filter with a matrix of red, green and blue squares, from which the otherwise colourblind sensor “demosaics” the colour information in the image, the X3 can record all three red, green and blue colours at each pixel location. Whew!

Add to this that the sensor used in the DP1 is enormous when compared with sensor found on other similar compacts such as Canon’s G9 or, say, Ricoh GX100. Both those cameras use a sensor about the size of your little fingernail with a diagonal of around 10mm.

The DP1’s sensor is 20.7 x 13.8mm and is essentially the same sensor found in Sigma’s SD14 DSLR and so offers an diagonal of around 28mm making it positively enormous in comparison. Add in the fact that the way the X3’s photocites are buried within the CMOS’s silicone (light of varying colours can only penetrate to certain depths and that’s how you can capture all three colours at each pixel location) colour fidelity is quite dramatic when compared with Bayer filter sensors.

It’s a bit of puzzle though since confusion reigns over the actual pixel dimension measurement. Because the pixels are together the actual image dimensions provided by the DP1 are 2652 x 1768-pixels so that’s 4.6-megapixels. Sigma (and Foveon) then multiply that figure by three but as you can see the actual image dimension looks fairly modest when compared with the latest 10- or 12-megapixel models out there using Bayer covered sensors.

However, the pixels on the X3 sensor are big so noise, until you get the top ISO 800 setting, is simply not an issue. Also, the amount of detail captured thanks to the fixed, 28mm wide-angle lens, and the large pixel size gives the apparent resolution of a camera with a third more pixels; akin, in fact, to a camera with around 8-megapixels by my estimation.

Yes, the files are smaller, but modest resizing using, say, Photoshop, can easily push the photos to a size that will print at 19 x 13in without much of a problem and they’ll be cleaner, sharper, and more colourful than equivalent Bayer sensor shots.

There’s no end of comment on these things online (just Google Foveon and you’ll see what I mean) but Sigma obviously like to quote the 14.6-megapixel total for its sensor, presumably for marketing purposes because as we all know, more pixels are better, right? Wrong.

The DP1 is a dramatic illustration that it’s not always the number of pixels that make a great shot (or better camera) but the size of the pixels themselves and their density on a sensor. The DP1 can shoot both JPEG and RAW files but shooting JPEG seems a nonsense since you’ll loose the benefits of the big X3 sensor.

The supplied Sigma Photo Pro software is easy to use but very slow and clunky to use, plus, the Foveon X3F RAW files are still not widely supported by other, less cumbersome RAW processing packages such as Lightroom.

Nevertheless, to get the most from the DP1’s sensor and lens, RAW is the way to go and like this slow software, the camera needs a measured approach in use too. The camera is a little larger than you’d think but not horribly so, it’s squared-off lines provide little to hang onto but the metal construction is tough enough.

The lens protrudes from the body when you switch the camera on, despite it not being a zoom and there’s detachable lens hood to help shade the thing from stray off-axis light. Use it though to ensure you get the best contrast and minimal flare in your photos.

A minimal set of buttons include a large top plate mode dial for the P, A, S and M settings plus the program, auto and a crude 320 x 240-pixel movie setting. “Zoom” buttons on the back activate the digital zoom (yep, you guessed it, leave that alone) or magnifying images in playback.

Auto, fixed landscape and manual focusing are all here but the manual focus is achieved via a small, freely rotating dial that should have ratchet stops as it’s too easy to knock out of focus once you’ve set it up.

There’s an exposure compensation button too and this needs to be used more often than I’d hoped, as the metering system seems a little temperamental, but, along with most of this camera (an its software), patience is the key to get the most from it.

You cannot rush the DP1. Writing a single RAW frame can take (gulp!) 7 seconds, though you can shoot three JPEG or RAWs in continuous mode before it locks up for a frustrating 15 seconds or so. A steady approach to the shooting process should not be rushed and helps get the most from the thing.

After all, all the key settings and features are buried in menus that are, in this day and age, a disaster. There are no "hard" button shortcuts to any key settings. The colour screen is murky too and unless you have it set to its brightest mode, it’s hard to use. Battery life suffers as a result too I’m afraid.

There’s an accessory optical VF-11 viewfinder that slots into the flash hot shoe which is an advisable purchase it will help get more from the camera’s battery. However, the limited AF system (you can only use one AF point of the nine available at a time) needs care in use as the narrow depth of field afforded by that bigger, APS-C sensor, means focusing is critical in close-up or complex subjects at bigger apertures.

And so, you get the idea. The DP1 is a camera that harks back to the days of yore in terms of control and handling and getting at the key settings and, to a degree its gross resolution. Think 2002 digicam technology and you’ll know what I mean. And even more importantly, the DP1 is eye wateringly expensive at £550, that’s more than most budget DSLRs with a kit lens that’ll have comparable sized sensors as well!


And so, the Sigma DP1 is a bit of a mixed bag. Thought of as a quality compact digital camera, the image quality is streets ahead of any of compact with a "normal" sensor and competes well with DSLR image quality and so makes it a realistic back up, for image quality at least.

But the issues around poor menu design and the handling make it a frustrating experience both when snapping and when processing on PC later using the Sigma Photo Pro software. If you’re going to use this tripod mounted for more studious work, or as an occasional quality snapper it’ll serve you well. But if you need something with a bit more snap on the performance side of things then it might not be for you. And you’ll need to be able to afford it too.

Simply the best image quality of any compact I’ve yet tested, but the price, performance and handling mean I suspect you’ll need to think long and hard to justify the outlay.

Writing by Doug Harman.