Sigma SD14: Information from Answers.com

Sigma SD14

Type	Digital single-lens reflex
Sensor	20.7 mm × 13.8 mm Foveon X3 sensor
Maximum resolution	2652 × 1768 × 3 (14.1 million active photoelements)
Lens type	Interchangeable (Sigma SA mount)
Shutter	electronic focal-plane
Shutter speed range	30 s to 1/4000 s, 2 min to 1/4000 s in extended mode
Exposure metering	TTL, full aperture, zones
Exposure modes	Programmed, shutter-priority, aperture priority, manual
Metering modes	Matrix, Center Area, C/Wgt Average
Focus areas	5 points, cross pattern
Focus modes	One-shot, Continuous, Manual
Continuous shooting	up to 3.0 frame/s
Viewfinder	Optical, pentaprism
ASA/ISO range	100–800 in 1 EV steps, 50 and 1600 in extended mode
Flash	pop-up, sync at 1/180 second
Custom WB	6 presets, auto, and custom
Rear LCD monitor	2.5-inch (63 mm), 150,000 pixels
Storage	CompactFlash(CF) (Type I or Type II) and MicroDrive(MD)
Battery	1500 mAhr 7.2 V Li-ion rechargeable
Weight	700 g (body only)
Retail info

The Sigma SD14 is a digital single-lens reflex camera produced by the Sigma Corporation of Japan. It is fitted with a Sigma SA mount which takes Sigma SA lenses.

The camera was announced on August 29, 2006 with a "teaser" advertising campaign^[1] and was unveiled at the Photokina trade show in Cologne, Germany on 2006-09-26.^[2] After production delays, Sigma announced the official release of the SD14 to be on March 6th, 2007.^[3] Sigma has released sample images on their website.^[4] Contrary to most consumer Bayer sensor based cameras, the Foveon X3 sensor does without anti-aliasing filters and is not susceptible to color aliasing due to the RGB color stacked pixels. Foveon sensors don't form artifacts like Bayer sensors; sharpening tools can be applied to create high resolution images. Foveon images are easily enlarged without the same artifacts and degradation seen in Bayer sensored images. The circular infrared dust-protector-UV/IR-blocking filter can be easily removed, converting the SD14 into an infrared-sensitive camera.

1 Lenses and focusing
2 Improvements from SD10
3 Output data options
4 See also
5 References
6 External links

Lenses and focusing

The Sigma SA lens protocol is a clone of the Canon EF protocol which provides a not so obvious but very interesting option that most Canon EF lenses will work seamlessly after exchanging the mount plate with the Sigma DSLRs, but without image stabilisation. Physically, the SA-mount is identical to the PK-mount with a reduced back-focus of 44.0mm (equals Canon EOS) as opposed to the 45.5mm of Pentax PK and M42.

PK-lenses fit, but should only be mounted when the rear protrusions have been dismantled. Such lenses will then focus beyond infinity and may contact the protective filter. A spacer ring (made e.g. of decopperized FR3 1.5mm circuit board) can be added between the PK lens body and its bayonet plate. Prime, as opposed to zoom-lenses often permit a simple resetting of the position of the focussing ring on helical inside. Zoom lenses converted this way will become vari-focals by losing the focus-setting as they are zoomed.

The spring that opens or closes the lens iris may have to be reset to work in the opposite direction. All M42 lenses work as is without problems with the SA/M42 converter, being rotated by 90°. Although the Nikon F back-focus at 46.5mm is well above the 44mm of the SD14, there is no adapter for the infinity focusing possible as, unlike with Canon EOS, the Nikon bayonet of roughly the same diameter will not fit inside the SA=PK bayonet. The M42 thread does, as taken care of by Asahi when introducing PK in the 70's. Lenses with equal or shorter back-focus (pre-EOS Canon, Minolta, Konica, Miranda) can only be adapted by discarding the old bayonet, milling off extra metal from the lens barrel and adding an SA = PK bayonet flange. Due to the (for a crop-DSLR) excellent viewfinder of the SD14 the missing auto-iris is not the problem it might seem to be, as primes from 45mm up focus comfortably on the screen down to f/5.6. The camera meters automatically via the AV setting with anything mounted on it or being mounted on, such a microscope. For this, the camera is always set to a virtual aperture of 1.0. The SD14's solid construction and decent size make it a desirable platform for laboratory and technical photography.

Improvements from SD10

The camera has a new body design with more rounded corners and is a little smaller than its predecessors, the SD10 and SD9. Like the previous models, it uses a Foveon X3 direct image sensor, this time with an improved pixel count of 2652 × 1768 × 3 photoelements (4.7 million locations, 14.1 million total photoelements). Since there are three layers of sensor elements for each pixel location, one each for red, green, and blue, Sigma and Foveon count 14 megapixels, counting all individual single-color sensor elements.^[5] Similarly, companies selling Bayer sensor cameras also count single-color sensor elements as pixels, as does Fujifilm with its Super CCD cameras, in which both large and small photosensors under the same color filter and microlens are counted as pixels.^[6]

Other improvements over the previous design include a built-in, pop-up flash, FAT32 support for larger-capacity CompactFlash storage cards, a higher continuous shooting speed of 3 frames per second, an upgraded auto focus system with 5 sensors, an AF assist lamp, an improved viewfinder with a 0.9 × magnification, an almost silent and more durable shutter rated at 100,000 actuations, a larger 2.5" LCD monitor, a USB 2.0 interface (but no firewire interface anymore), and a proprietary rechargeable (Minolta NP-400 compatible) lithium ion battery system with a claimed 500 shot (user experience closer to 150) capacity.

It is also claimed that the re-design of the shutter has eliminated the problem of particles flaking off of that mechanism and onto the sensor. Sigma has also revised the infrared filter (dust protector), it is now a somewhat fragile round snap-in design rather than the square, sturdier screw-in version of the SD10. It is easy to remove, but tricky to replace without breakage (requiring study of the manual beforehand). Its major fault lies in the crop of the visible spectrum at 660nm rather than 700 to 750nm according to the near infra-red perception of the human eye. This leads to unnatural azure rather than neutral blue sky colours. Attempts to correct this with software are limited when the green of foliage needs to be maintained. An alternative wider-band filter for outdoor photography could solve the problem. The purity of blue is over-emphasized, whereas the quality and tonal differentation of foilage-green is sub-standard, often tending towards a yellowish olive on a sunny day. Outdoor photography with overcast skies gives better results, while general indoor and studio-photography are strong points of the camera and not affected.

Output data options

The camera can output a RAW file size of 14.1 million sample values, organized as 2652 × 1768 × 3, or a JPEG image up to 14 megapixels, or 4608 × 3072 (interpolated) pixels. The camera's ISO range extends from 100 to 800 (or 50 to 1600 in extended mode). There is not much degradation going from 100 to 200 and even 400.

In the RAW file, each of 4.7 million triples of digitized data from the sensor contains three measurements taken at three different depths within the silicon chip. The penetration of light into silicon is dependent on the wavelength of the light; therefore, the red, green, and blue values can be independently calculated at each of 4.7 million locations.

This is in contrast to the approach utilized in a Bayer sensor, which can only measure one color channel at each location, and must interpolate the remaining color information based on the neighboring values. The 10.2 million value RAW output from the Sigma SD10 has compared favorably with the output from 6 to 8 megapixel Bayer-sensor DSLR cameras. An equivalence to 9 megapixel from a Bayer DSLR has often been cited.^[7] The SD14 image quality has been compared to 8-12 megapixel Bayer-sensor cameras, depending on light conditions and types of colors present in the image.^[8]^[9]