Sigma SD15 Preview
The Sigma SD15 is the successor to the Sigma SD14. Both are characterized by their use of a Foveon sensor.
Unlike the sensors in most DSLRs, which use separate pixels to detect red, green and blue light, in a Foveon type sensor each pixel generates a red, green and blue signal. The Foveon pixels take advantage of the fact that light of different colors can penetrate to different depths in silicon. By measuring the signal generated at different depths, the color of the light can be determined.
So far the only DSLRs to use Foveon sensors have been made by Sigma and the sensor used has 4.65 million photosites. However, the pixel count is multiplied by three because each site generates signals for red, green and blue. Sigma and Foveon call this a 14.1MP sensor. Though you can’t really directly compare it with a conventional 14MP sensor (using a Bayer color matrix). Tests show that a 4.65MP Foveon sensor generates higher image quality than a 4.65MP conventional sensor, but it’s not really equal to a 14MP conventional sensor. Perhaps it’s more closely equivalent to a 10MP Bayer matrix sensor. The comparison is
difficult because it depends if you look at B&W resolution or color resolution, and it depends on the quality software used to eliminate moire patterns, which tend to be much stronger with conventional Bayer matrix sensors.
It’s a bit of a mixed bag. In some respects the 4.65MP (or 14.1MP) Foveon sensor may be better than a 10 MP conventional sensor, in some respects it may be worse. It’s certainly interesting technology, though it really hasn’t caught on with anyone but Sigma.
The Sigma SD15 is quite similar to the earlier Sigma SD14. They use the same sensor, but the SD15 has a more advanced processing engine (the “True II Processor”) and the LCD is increased in size from 2.5" to 3". In all other respects the two cameras appear to have identical specifications and features.
The Sigma SD15 is compatible with Sigma’s own line of lenses. Though the mount is somewhat similar to the Canon EOS mount, Canon lenses cannot be used on Sigma DSLRs.
h2. Official Sigma SD15 Press Release
Sigma announces the development of the SD15, a 14 megapixel (2,652×1,768×3 layers) Digital SLR camera.
The Sigma Corporation (COO: Kazuto Yamaki) is pleased to announce the new SIGMA SD15 digital SLR camera.
This camera is the latest model in Sigma’s digital SLR camera SD series, powered by the 14 megapixel Foveon X3 direct-image-sensor it can capture all primary RGB colors at each and every pixel location arranged in three layers.
The developing SD15 incorporates the “TRUE II” new image processing engine. It provides high resolution power and reproduces high definition images rich in gradation and impressive three-dimensional detail. Incorporation of the large 3.0 inch LCD monitor and improved processing speed provide ease of operation of the camera.
h3. Development of the SD15
Since October 2002, Sigma has introduced three digital SLR cameras, the SD9, SD10 and SD14 to the market. In March 2008 Sigma also introduced a high-end compact digital camera, the DP1 which uses the same large image sensor as is featured in Sigma’s digital SLR cameras. They have established a strong following from a wide range of photographers, both amateur and professional. Photographers expressed a desire to incorporate the image processing engine “TRUE”, which is used in the DP1, into a digital SLR camera. In order to meet this demand, the SD15, with high resolution direct image sensor, has been designed around the new “TRUE II” image processing engine. This combination delivers superior image quality as well as improved processing speed, operation and performance.
h2. Brief Specifications of the Sigma SD15
|Sensor||Foveon, 2640 × 1760 pixels (x3), 20.7 × 13.8 mm|
|Lens Mount||Sigma SA Bayonet|
|ISO settings||100, 200, 400, 800, 1600 (extended mode)|
|Shutter speeds||1/4000 sec to 30 sec + Bulb|
|Exposure compensation||-3 to +3 EV in 0.3 EV steps|
|Metering||8-segment, center, cw average|
|Continuous Drive||3 fps|
|Storage||Compact Flash Type I or II|
|LCD||3.0 ", 150,000 pixels|
|Weight (inc. batteries)||750 g (26.5 oz)|
|Dimensions||144 × 107 × 81 mm (5.7 × 4.2 × 3.2 in)|
Original text ©2008 Bob Atkins.