Sigma’s SD1 has been a hot topic on the online photo forums, in part, for its remarkable Foveon X3 image sensor and, in part, for its equally remarkable price. The sensor offers three times the pixel count of previous Sigma DSLRs and a rugged, straightforward body. The unique Foveon X3 sensor records all three primary colors (red, green and blue) at every pixel site, not just one primary per pixel like conventional sensors. This does away with moiré problems and the resulting need for a blurring low-pass filter, giving the Foveon sensor potentially better color reproduction and higher resolution than a conventional sensor of equal horizontal-by-vertical pixel dimensions.
High-Res Foveon X3 Sensor
Sigma bought Foveon in 2008, and the new sensor in the SD1 is the first issued since that acquisition. It produces images measuring 4704x3136 pixels (about 15 megapixels), but contains three such layers for a total of 48 megapixels. With the X3 sensor’s unique properties, this should mean images equivalent to those of a 30-megapixel conventional sensor. We’ll have to see when we get a test camera. The new TRUE II (Three-layer Responsive Ultimate Engine) image processor optimizes output from the X3 sensor.
Twin Control Dials
Like previous Sigma DSLRs, the SD1 is a straightforward camera, with few bells and whistles. The dial to the right of the finder directly selects the exposure mode (program, shutter-priority or aperture-priority AE, or metered manual) and three user-chosen custom settings. The dial to the left of the finder provides direct access to drive modes, mirror prelock and auto-bracketing, and also serves as an
Sigma SA Lens Mount
Sigma is best known as a lens maker and offers a wide range for the SD-series cameras, including the new SD1. These currently number more than 50, from a 4.5mm ƒ/2.8 circular fisheye and an 8-16mm superwide zoom to an 800mm ƒ/5.6 supertele and the world’s fastest 500mm, the 200-500mm ƒ/2.8 zoom. Many feature Sigma’s OS optical-stabilizing system.
Few pro-oriented DSLRs have a built-in flash unit, but the SD1 does (GN 11 in meters, ISO 100). The camera has a hot-shoe for dedicated flash units and a PC terminal for studio flash systems. Maximum flash-sync shutter speed is 1⁄180 sec.
Featuring a magnesium-alloy body, the SD1 is the first weather-sealed Sigma DSLR.