Sigma SD14

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http://reviews.cnet.co.uk/digitalcameras/0,39030233,49291313,00.htm

Reviewed 9 July 2007

Reviewed by Philip Ryan

No one makes a digital SLR like Sigma. Ever since the company started making them, it has eschewed the CMOS and CCD sensors employed by most manufacturers and opted for three-layer sensors made by a company called Foveon.

In Sigma's newest model, called the SD14, each of the three layers includes 4.7 megapixels. Sigma misleadingly markets the camera as a 14.1-megapixel camera, but while you can expect significantly more resolution than you'd get from a 4.7-megapixel camera, it's nowhere near what you'd get from a 14.1-megapixel CMOS- or CCD-based model. Fervent fans of the Foveon sensor say that the three independent layers yield better colour accuracy than the other sensor technologies currently on the market, but we'll discuss that more a little later.

Design
The SD14's body design is very similar to its predecessor, the SD10. While not the fanciest design, it is functional and has a comfortable, contoured grip. Sigma places most of the hard-button controls in logical, easy-to-reach places. Two dials atop the camera let you select the drive mode and exposure mode. The drive dial also doubles as the on/off switch. While their knurled edges provide a good grip, the camera did inadvertently turn on in my bag on more than one occasion.

Worse than that, though, are the menu-based controls, which feel like they belong on an entry-level point-and-shoot instead of a pricey dSLR. You can get to a menu for ISO, white balance, image size and image quality with one button press, but once there, you press one of the four-way control buttons to change each setting. Unlike some cameras, which let you move either way through the choices (moving from ISO 200 to either 100 or 400, for example), the SD14 makes you cycle forward through all possible choices. That means that if you want to go from ISO 200 to 100, you have to press the up controller four times after pressing the button to access the menu.

Most shooting-related settings that aren't in the four-way menu are accessed by repeatedly pressing the Func button. That means that if you want to activate the extended ISO range so you can shoot at ISO 1,600, you have to press the Func button seven times, remembering to hold it down the seventh time, and then turn the selector dial that surrounds the shutter button to change the setting.

Keep in mind that both the drive and exposure mode dials have more than half their possible click stops empty. Sigma could have easily put all these functions on these dials instead of making you remember how many button presses it takes before you have to hold down the Func button just so you can change the flash mode (the answer is three, in case you're wondering).

Features
Outside of its sensor, the SD14 doesn't have many interesting or unique features. However, it does have a removable infrared-cut filter. If you didn't already know, almost all digital cameras have an IR-cut filter mounted in front of their sensors to remove the infrared spectrum of light, since it interferes with the camera's ability to capture the images we all love.

Just as you can load a film camera with infrared-sensitive film, however, you can remove the SD14's IR-cut filter, put the appropriate IR-photography filter on the front of your lens, and shoot IR photos. If you've enjoyed shooting IR photos with your film camera, the Sigma SD14 is one of the few digital cameras that will let you continue with that hobby.

Another interesting, but not unique, feature of the SD14 is that its built-in flash will let you wirelessly control one of Sigma's EF-500 DG Super SA-STTL hot-shoe flash units. The camera even includes three different wireless channels, in case you run into interference.

For a camera in this price range, we were rather disappointed with the 64mm (2.5-inch) LCD screen. Not only is it on the small side compared to the 76mm screens that have been popping up on many new SLRs, but it only has 150,000 pixels, while most 64mm LCDs on competing cameras have 230,000 pixels. In fact, you can find 64mm 230,000-pixel screens on many point-and-shoot cameras these days. Image previews look coarse in places, due to the lower resolution, but then, you can't rely on any camera's LCD for a really accurate representation of your images anyway.

One of the biggest gripes about Sigma's previous dSLRs was the lack of native JPEG capture. While those models forced you to shoot raw and then process your images on your computer to get a standard file format, the SD14 will process images in the camera and yield standard JPEG images without the need for a computer. However, unlike most dSLRs, the SD14 won't let you shoot both raw and JPEG files at the same time. Since we usually do shoot both, this became rather frustrating over the course of our review process.

Performance
In our tests, the Sigma SD14's performance was not impressive, especially considering its price. The camera took 1.8 seconds to start up and capture its first JPEG. After that, it took 0.8 seconds between JPEGs with the flash turned off, and 1.5 seconds between JPEGs with the flash turned on. When capturing raw images, the SD14 takes 0.9 seconds between shots without flash.

Shutter lag measured 0.7 seconds in our high-contrast test and 1.4 seconds in our low-contrast test, which mimic bright and dim shooting conditions, respectively. In continuous shooting mode, we were able to capture highest resolution and highest quality JPEGs at an average rate of 2.3 frames per second.

Shooting speed (in seconds)
(Shorter bars indicate faster performance)

Time to first shot

Raw shot-to-shot time

Shutter lag (dim light)

Shutter lag (typical)

Olympus Evolt E-410

1.4

0.7

0.9

0.4

Nikon D40x

0.2

0.8

0.9

0.4

Canon EOS 400D

0.3

0.6

1.1

0.4

Sony Alpha DSLR-A100

1

0.5

1.6

0.4

Pentax K10D

0.5

0.5

1.6

0.5

Sigma SD14

1.8

0.9

1.4

0.7

Typical continuous-shooting speed
(Longer bars indicate faster performance)

Frames per second

Olympus Evolt E-410

3.3

Pentax K10D

3.2

Nikon D40x

3

Canon EOS 400D

2.9

Sony Alpha DSLR-A100

2.5

Sigma SD14

2.3

 
Image quality
Under the right circumstances, the Sigma SD14 can create very good images, but once you move up to higher ISOs, the image quality degrades significantly. At ISO 100 or ISO 200, colours look quite accurate and the camera's white balance is generally neutral. If anything, colours looked slightly over-saturated in our test images, especially reds and oranges.

As you increase the ISO, however, not only do you see a increase in noise, but the entire colour profile of the camera shifts. Our lab test images took on a serious magenta cast at ISO 1,600, and green patches on our colour-checker chart turned nearly neutral grey. At the same time, a careful eye will notice that certain colours, including skin tones, look just slightly more accurate with the Sigma than they do with many CMOS- or CCD-based cameras.

ISO noise, and the noise-reduction techniques that go along with it, don't behave the same way in the SD14 as they do with most other cameras. While noise is often more noticeable in the darker parts of the greyscale in most cameras, the Sigma spreads its noise out more evenly among the colours. Also, the noise tends to manifest itself as off-colour blotches with less defined edges than the speckles that appear in most other SLRs.

We began to see noise in our test images at ISO 200, but at that point it is only really noticeable on monitors and is minimal at that. This increased significantly at ISO 400, while decreasing the overall dynamic range, shadow detail and finer detail. At ISO 800 noise becomes even more pronounced, taking on a tighter, more grain-like patter while further chipping away at shadow detail and finer detail.

At this point, we also noticed a pronounced decrease in the saturation of greens, and erratic colour shifts in other parts of the colour spectrum. At ISO 1,600, noise takes on a heavy coating of grain with separate, larger, very noticeable off-colour blotches appearing, and as mentioned above, greens lost almost all saturation. Given this camera's bizarre performance, we suggest you don't use it above ISO 400. This severely limits its usefulness.

Conclusion
If you're only intending to use this camera below ISO 400, for studio portraits, or perhaps for landscapes or infrared photography, then you may want to consider the Sigma SD14. However, even then that probably wouldn't make sense, since there are many other cameras that are available for the same price or less that can provide just as good or better performance and image quality.

In fact, here is a list of five cameras that cost not much more than half of the SD14's approximately £800 street price (at time of publication) and will give you significantly faster performance and much better image quality performance across an equivalent sensitivity range: Canon EOS 350D, Canon EOS 400D, Nikon D40x, Pentax K10D, Sony Alpha DSLR-A100. On some of those, you'll lose the wireless flash control capability, but other than that, you'll get equivalent or increased resolving power, and a much more versatile and enjoyable shooting experience.

Additional editing by Nick Hide