Featuring a rugged, yet lightweight magnesium-alloy body, the SD1 Merrill is sealed against dust and moisture. A 3.0-inch, 460K-dot LCD monitor provides easy viewing of just-shot images and menus. The bright eye-level pentaprism SLR viewfinder shows 98% of the actual image area. Images are stored on Type 1 CompactFlash cards (UDMA-compatible); there's a single card slot. The shutter is rated at more than 100,000 exposures. To minimize vibration, the SD1 Merrill uses separate motors for mirror operation and shutter charge.
The SD1 Merrill features an 11-point AF system, with twin cross sensors for added precision. You can select any of the AF points manually, or let the camera do it. The AF system functions in light levels down to EV -1.
Sensor, Processor & ISO Range
Sigma's original SD1 DSLR featured a new version of the unique Foveon X3 Direct Image Sensor with three times the pixel count of its predecessor and image-quality improvements to match. Now, Sigma has replaced the original SD1 with the SD1 Merrill (named in honor of late Foveon-sensor co-creator Richard Merrill), with the same performance and characteristics as the original SD1, but with a significantly lower price tag ($2,299 estimated street price). Sigma is offering "Sigma points" to those who bought the original SD1, which can be exchanged for Sigma products.
The photodiodes in image sensors are color blind; they detect the amount of light that strikes them, but not its color. To produce color information, conventional sensors are covered by a grid of red, green and blue filters so that each pixel records just one primary color of light (red, green or blue). The missing color data for each pixel is obtained via sophisticated interpolation of data from neighboring pixels. The Foveon X3 sensor takes advantage of the fact that light penetrates silicon to different levels depending on wavelength (color). It stacks its 44.4 million effective pixels in three 14.8-megapixel layers. Because of this stacking, each of the 4.8 million surface pixel sites can record light of all three primary colors. As a result, the Foveon sensor doesn't require the low-pass blurring filter needed by conventional RGB-filtered sensors to avoid aliasing artifacts, and that results in greater resolution for a given horizontal-by-vertical pixel count. By most accounts, the 4704x3136-pixel images delivered by the SD1 Merrill's Foveon sensor provide resolution equivalent to those of a 25- to 30-megapixel conventional sensor. The ISO range is 100-6400.
Our preferred three-lens landscape kit for the SD1 Merrill (with its 1.5x focal-length factor) starts with a superwide zoom. Sigma makes three good contenders. We like the combination of focal range, sharpness, contrast and value afforded by the 10-20mm F4-5.6 EX DC HSM. The 8-16mm F4.5-5.6 DC HSM, 10-20mm F3.5 EX DC HSM and 12-24mm F4.5-5.6 DG HSM II are all good options as well. For a midrange zoom, our choice is the 17-50mm F2.8 EX DC OS HSM; the 17-70mm F2.8-4.0 DC Macro OS HSM is a lower-priced option. For the telezoom, the 50-200mm F4-5.6 DC OS HSM fits the bill focal-length-wise, but the APO 70-200mm F2.8 EX DG OS HSM is better suited to the SD1 Merrill optically.
Other Important Features For Landscape Shooters
Like previous Sigma DSLRs, the SD1 Merrill favors simplicity over bells and whistles. Twin control dials provide direct access to exposure modes (program, shutter-priority, aperture-priority and metered manual), drive modes and user-chosen custom settings; you even can activate mirror prelock without going into LCD monitor menus. There's also a built-in flash—a rarity on a pro DSLR—along with a hot-shoe for dedicated external flash units and a PC connector for studio flash systems (all handy for fill light on nearby objects and macro work). Maximum flash-sync shutter speed is 1⁄180 sec. A dust protector over the image sensor can be removed for easy cleaning (and since the protector doubles as an infrared filter, its removal makes it possible to do infrared photography, a task not easily done with other DSLRs).
The 77-segment evaluative metering system coordinates with the 11 AF points to optimize exposures. There's also center-weighted and spot capability.
The SD1 Merrill doesn't have video capability.