Sigma DP3 Merrill Preview
by Mike Tomkins
For several generations now, there's been a clear pattern to Sigma's DP-series of fixed-lens, large-sensor cameras. Each generation has had just two models, closely related and differing mostly in their choice of lens. For the first time in a half decade, the pattern has changed with the introduction of a third DP-series camera, the Sigma DP3 Merrill.
Since they're based around fixed, prime lenses, the optic used by each DP-series model will define which camera is best suited to your needs. The DP1 (2006), DP1s (2009), and DP1x (2010) shared a wide-angle 28mm-equivalent f/4 prime, while the DP1 Merrill boasted a similar -- but brighter -- 28mm-equivalent f/2.8 optic. The DP2 (2008), meanwhile, introduced a 41mm-equivalent f/2.8 prime that was retained for the DP2s (2010) and DP2x (2011), before being replaced by a slightly more telephoto 45mm-equivalent f/2.8 prime for the DP2 Merrill.
The Sigma DP3 uses a new 50mm f/2.8 prime lens, which -- after accounting for the 1.5x focal length crop of its APS-C image sensor -- is the equivalent of a 75mm optic on a 35mm camera. The lens design features 10 elements in eight groups, and there's a seven-bladed aperture diaphragm. Focusing is possible to as close as 8.9 inches (22.6cm), and maximum magnification is 1:3 (0.33x). There's no image stabilization, and the DP3 uses a nine-point contrast detection autofocus system. Although a lens hood isn't included in the product bundle, one is optionally available, and the DP3 also accepts 52mm threaded filters.
Unsurprisingly given its focal length and aperture, the lens is much larger than those of the other two current models. Body width and height are identical, at 4.8 inches (121.5mm) x 2.6 inches (66.7mm), but at 3.2 inches (80.6mm), the DP3 is about three quarters of an inch (~20mm) deeper than its siblings. It weighs about 14.1 ounces (400g) without battery and memory card, where the DP1M is 12.7 ounces (360g), and the DP2M is the lightest at 12.5 ounces (355g).
At 75mm-equivalent, the DP3's lens is a medium telephoto that's rather closer to the classic 85mm portrait lens than the wide-angle lenses of its siblings, so it'll likely make for a good portrait shooter. It will also work nicely for street shooting if you don't mind being further back from your subjects than typical, but it may prove rather tight in confined spaces. The DP1 is closer to a normal lens that gives a natural-looking field of view, while the DP2 sits somewhere in between.
In other respects, the Sigma DP3 is again very closely-related to its current siblings. It shares the same 15.4-megapixel Foveon X3 CMOS image sensor as seen in both previous fixed-lens Merrills, as well as the SD1 DSLR and its rebranded variant, the SD1 Merrill. Like all Foveon sensors, this captures full color information at every pixel location, unlike other cameras which typically capture only red, green, or blue at each pixel, and then interpolate the other two colors. This leads to a significant increase in perceived resolution beyond that you might expect from its megapixel rating; in testing of the same sensor in the Sigma SD1 we've found it to compare well against a 24-megapixel Bayer-filtered sensor. (But not by as much as the 46-megapixel rating used by Sigma might suggest.)
Full-resolution burst shooting is possible at up to four frames per second, for seven raw frames. By switching to medium quality JPEGs, you can increase this to a rate of five frames per second for 14 frames. ISO sensitivity ranges from 100 to 6,400 equivalents, with only a range of ISO 200 to 800 equivalents available under automatic control.
As a camera aimed at experienced photographers -- consumers likely will be put off by the fixed, prime lens -- the Sigma DP3 provides no scene or other creative modes, relying only on the more standard program, aperture-priority, shutter-priority, and manual modes. Shutter speeds range from 1/2,000 to 30 seconds, although the available range changes with lens aperture, and +/- 3.0 EV of exposure compensation is available in 1/3 EV steps.
On the rear panel, there's a high-res 3.0-inch LCD panel with a total dot count in the region of 920,000, equating to an approximate VGA array of 640 x 480 pixels. There's no built-in flash strobe, but a standard hot shoe on the top deck provides for external strobes. Connectivity includes standard-def NTSC / PAL video output and USB 2.0 High Speed data, and power comes from a proprietary BP-41 lithium-ion rechargeable battery pack. Images are stored on Secure Digital cards, including the higher-capacity SDHC and SDXC types.
As with its siblings, the Sigma DP3 Merrill is largely aimed at still imaging. Although it can capture movies, it can only do so at a standard-definition resolution of 640 x 426 pixels. That's a standard VGA frame width, but with a non-standard 3:2 aspect ratio; the result is letterboxed inside a 4:3 aspect VGA file.
The Sigma DP3 will arrive in the US market from March 2013. Pricing is set at around US$1,000.