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The website Four Thirds User has just posted a review of the Sigma 105mm f/2.8 EX DG Macro Four Thirds system lens. This lens is also available for non-four thirds systems as well.

They measure very good results in chromatic aberration, vignetting, and distortion. Sharpness appears to be consistent throughout the frame, with a slight different between center sharpness and corner sharpness only down at f/2.8, with consistent results across the frame at all smaller apertures.

The sharpness itself isn’t as good as the two lenses they compared it with, the Olympus Digital Zuiko 50mm f/2.0, and the Olympus Digital Zuiko 14-42mm f/3.5-5.6 kit lens that’s available with the Olympus E-510 body. However, the Sigma 105mm had better chromatic aberration and geometric distortion measurements than the 14-42mm.

In the end, they do recommend the lens with a rating of 85%, with some caveats:

There is much to like about the Sigma 105mm Macro EX DG for Four Thirds. It feels solidly built and is positive in handling and results. It’s also a very versatile lens, useful for portraits and medium telephoto work, especially in low light, as well as macro work. The Sigma 105 Macro is more effective as a macro lens than the more expensive Olympus Digital Zuiko 50mm f/2.0 Macro, which only goes to 1:2 reproduction, though optically the Olympus lens has the edge. You can get similar 1:1 macro reproduction to the Sigma 105 with the considerably cheaper, smaller and lighter Olympus Digital Zuiko 35mm f/3.5 Macro, though this is slower, less robustly constructed and arguably less versatile as a general purpose lens. Sigma’s manual/auto focus mode switching takes some getting used to, but the mechanical manual focus actually works very well. In auto focus, Sigma hasn’t endowed this lens with its HSM sonic motor system, so the focus action is not particularly fast or refined. I’ve noted mixed feelings about the finish of the Sigma 105; the matt finish seems to be hard wearing, but isn’t as attractive as the traditional semi-shiny finish found on many other lenses.

Be sure to read the full review for all the details, and for sample photos taken with the lens as well.

TrustedReviews has posted a full review of the Sigma SD14 digital SLR camera. The Sigma cameras tend to fly under the radar in the DSLR world, but they are fairly interesting. Sigma markets the SD14 as a 14 megapixel camera, which isn’t entirely accurate due to the tricky world of Foveon.

The SD14 is the only current DSLR to use the Foveon X3 Direct Image CMOS sensor, which, unlike the standard Bayer sensor, is able to detect a full range of colors at every pixel. The vast majority of digital cameras can only detect one color at each pixel (usually red, green, or blue) and then the actual color of that pixel is interpolated based on what the neighboring pixels picked up.

And according to the review, you do get a big advantage from the sensor, giving excellent picture quality:

Of course the whole point of the SD14 is its final picture quality, and here is where it excels, but it’s worth noting a few points when comparing it to other cameras. The Foveon X3 sensor captures all colours at all pixel locations, but calling it a 14-megapixel sensor is bending the truth a little. In fact it has a sensor resolution of 2,652 X 1,768 pixels, which is only 4.7 megapixels, but this is multiplied by three because there are three separate sensors at each site, which is where the 14-megapixel figure comes from. Comparing images shot with the SD14 to the numerous 10-megapixel DSLRs that I’ve tested over the past year or so, the overall level of detail is clearly higher, although not by much. However it is in colour reproduction and dynamic range that the SD14 really shines. Converting the lossless 12-bit RAW images to 16-bit TIFF image files produces results that I would compare favourably to high quality colour transparency film, with a dynamic range of around eight stops, which is significantly higher than most other DSLRs.

Unfortunately, the ISO sensitivity is pretty poor, only going up to 800 ISO, and the noise levels are much higher than you’d expect from a DSLR. According to the review, the noise at 800 ISO makes it pretty much unusable, and is still fairly intrusive at 400 ISO. Those are far worse results than other digital SLRs, and, at least for me, being able to bump up the ISO for low-light shooting is one of the main reasons to use a DSLR over a point and shoot. The SD14 just won’t work well in that situation.

If you look at the sample pictures in the review, you can see that it fails pretty badly, too. At ISO 800 you also get splotchy colors and often a green cast, along with your generous helping of noise.

One other downside is somewhat slow performance writing images to the memory card.

The camera itself is apparently well-built, if a little on the heavy side if you’ve gotten used to small and light cameras like the Olympus E-410 recently, as with the TrustedReviews reviewer:

It measures 144 X 107.3 X 80.5mm and weighs 750g including the battery, which is about the same size and weight as semi-pro cameras such as the Canon EOS 30D or the Pentax K10D, and much larger and heavier than any of the 10-megapixel mid-range or entry-level cameras such as the Sony A100, Nikon D40x or Canon EOS 400D. It is a bit smaller and lighter than the D200 though. Fortunately that size and weight translates into solid construction and excellent build quality. The body is high-density plastic over a metal chassis, but it is very well made with close tolerance on all joints and control mountings. Sigma has been making some of the best third-party lenses in the world for over 40 years, and that experience shows in the construction of the SD14.

Interestingly, RAW conversion with Adobe Camera Raw in Photoshop is not recommended according to the review, because the results are significantly worse than what you get with the included conversion software, Sigma Photo Pro 3.0. That might be a bit of a stumbling block to photographers that enjoy their current Photoshop-based workflow.

Be sure to read the full review and check out the sample images. TrustedReviews gives the SD14 a 7/10 overall, but a 10/10 for image quality. Personally, I don’t think it should be able to get away with 10/10 based on that high ISO performance, but I’m guessing they’re just looking at 100 ISO best case quality for that rating. Since that doesn’t feel like real world use to me, I have a hard time agreeing with that number based on their sample images and what they write in the review.

Feel free to leave comments if you have a dissenting opinion, of course!

Sigma has two new Nikon lenses coming out. The first is a 18-50mm F3.5-5.6 DC HSM, designed for APS-C sized sensors such as the Nikon D40. The second lens is a 55-200mm F4-5.6 DC HSM, also for APS-C sensors.

The 55-200mm looks nice and compact, at just 3.3 inches long and 310g (10.9 oz). FYI, HSM is Sigma’s “Hyper Sonic Motor”, similar to USM on a Canon lens. It gives you faster and quieter focusing than the regular (unhypersonic?) motor.