Camera Test: Sigma SD14

On older Sigma DSLRs, our biggest complaint was that we could shoot only RAW files. No longer. The SD14 lets you capture RAW or JPEG files (though not RAW + JPEG), with several compression and resolution options for JPEGs. We discovered, though, that the 14MP Super Hi JPEG format is merely an interpolated version of the 4.7MP Hi Quality JPEG, taking up much more storage space without offering a significant image-quality or print-size advantage.

Another gripe? While we could set the color space of JPEG images to Adobe RGB, the color space kept changing back to sRGB whenever the SD14 went to sleep or was turned off. (Sigma recently released a firmware download to fix it.)

You need Sigma's Photo Pro 3.0 software, which comes with the camera, to convert the SD14's RAW images to 8-bit JPEGs or to 8- or 16-bit TIFFs. While it's not the most sophisticated RAW utility -- lacking high-level controls such as curve, chromatic aberration, and lens distortion adjustments -- it does a far better job processing the SD14's RAW files than the current version of Adobe's Camera RAW.

Our image quality tests came down in favor of RAW files over JPEGs. In JPEG mode at ISO 100, the SD14 captures detail on par with an 8MP DSLR such as the Canon EOS Digital Rebel XT. Combined with an Extremely High color accuracy (9.9 Delta E), JPEGs earn an Extremely High image quality rating.

But in RAW, also at ISO 100, the SD14 performs more like a good 10MP DSLR, capturing about 10 percent higher resolution and Excellent color, earning it an Excellent image quality rating. Still, NEF RAW files from the $920 (street) 10.2MP Nikon D80 show higher detail. So this is not what you'd expect from a camera billed as having 14.1 megapixels.

At higher ISOs, the difference between JPEG and RAW files becomes painfully obvious. At ISO 400-800, RAW files are vastly superior to the JPEGs produced in the camera, most evident in shadows and darker-colored areas, which block up and get very noisy in JPEGs. In fact, by ISO 800, JPEGs made in-camera had such unusual colors and extreme shadow noise in multiple patches on our GretagMacBeth ColorChecker DC test target that we had to give them a thumbs-down -- even though the average color accuracy across all 180 patches tested Extremely High (8.5 Delta E), and noise in the neutral gray patch was Moderate (2.4).

Apparently, the SD14's internal image processor has a hard time converting high-ISO RAW data into JPEG form, while the supplied computer software handles the job more efficiently. The image processor also takes a glacial 8 to 10 sec to clear the buffer for another shot after a burst sequence of up to a mere six frames at 3 fps. That's not even in the same ballpark as the burst rate and capacity of competitive DSLRs.

In all, the camera handles well, opens creative doors with IR, and is technologically unique. But the promise of 14.1MP doesn't pay off. And given what you can find in today's DSLR market for $1,600, we see the virtue in shopping around.