Unveiled: Sigma dp Quattro Digital Cameras

 

 

 

 

Sigma has just updated their line of dp series fixed-lens compact digital cameras with a new sensor and image processor design and, subsequently, three new camera models encompassing the most common prime focal lengths used. This new line, called dp Quattro, in respect to the new image-sensor design, is characterized by updated sensor and processor technologies, as well as a unique body shape that marries form and function into an intuitive shooting experience.

 

Foveon X3 Quattro Direct Image Sensor

The core technology, which separates Sigma's digital cameras from any other, is its use of a Foveon direct image sensor. Unlike other sensor technologies that utilize a mosaic design across a single horizontal plane, the Foveon sensor uses a vertical design that stacks three layers of photodiodes within the silicon sensor, with each layer corresponding to a different color of RGB. Bayer array and other horizontally designed sensors assign an RGB value to each pixel, whereas Foveon sensors enable each pixel to record hue, chroma, and color value independently and accurately with no color interpolation required. The result of this process is a richly colored image with smooth tonal and value gradations, akin to the way film looks and works. Additionally, this sensor design alleviates the need for an optical low-pass filter, in order to attain overall sharper imagery with greater resolution.

With this principle in mind, Sigma set out to redevelop this sensor structure further in order to produce even higher resolution and image quality with lower noise levels. The new Foveon X3 Quattro sensor utilizes the same vertical design of past Foveon sensors, but employs a 1:1:4 ratio where the top layer is divided into quadrants (hence, Quattro). This enables a 30% increase in resolution compared to previous iterations of the Foveon, as well as more resolved noise characteristics and faster image processing due to the decreased volume of image data being processed. The APS-C image sensor delivers an effective resolution of 29MP; however, when broken down into individual photodiodes, it equates to the total resolution of a 39MP Bayer sensor.

TRUE III Processing Engine

Optimized to process the data provided by the Foveon X3 Quattro direct image sensor, the new TRUE (Three-layer Responsive Ultimate Engine) III has been developed. This processing engine incorporates Sigma's proprietary algorithm, used to decipher the immense amount of image data created by the three-layered sensor, and produce a richly detailed image sans any color aliasing or other image deterioration. The redeveloped sensor and processor combination also avails a top native sensitivity of ISO 6400 with reduced overall noise.

Prime Lens Design

As with previous series of dp cameras, Sigma has positioned this line to comprise three separate camera models, each of which features a prime lens of a standard focal length. The dp2 Quattro is the first camera developed in this series, and features a 30mm f/2.8 lens, which offers the same field of view as a 45mm lens in the full-frame, 35mm format. This normal-length lens and bright f/2.8 maximum aperture is well suited to everyday shooting due to its natural perspective, as well as its ability to excel in low-light conditions and produce shallow depth of field. Further installments in the dp Quattro series will see the dp1 Quattro and dp3 Quattro cameras, which will feature 19mm f/2.8 (28mm equivalent) and 50mm f/2.8 (75mm equivalent) lenses, respectively.

Redeveloped Form Factor

The most visually striking update to these cameras is the use of a completely redesigned body shape, which incorporates a well-balanced form offset by an ergonomic right-hand grip, dual top control dials, a 3.0" 920k-dot LCD monitor, and a lens design featuring a manual control ring.

Sigma dp Quattro
Image Sensor	Foveon X3 Direct Image Sensor (CMOS type)
Image Sensor Size	23.5 x 15.7mm (APS-C)
Color Photo Detectors	Effective Pixels: Approx. 29MP T (Top): 5424 x 3616 / M (Middle): 2712 x 1808 / B (Bottom): 2712 x 1808 Total Pixels: Approx. 33MP
Storage Media	SD, SDHC, SDXC memory card
File Format	Lossless compression RAW (14-bit), JPEG (Exif 2.3), RAW+JPEG
JPEG Image Quality	FINE, NORMAL, BASIC
Aspect Ratio	21:9, 16:9, 3:2, 4:3, 1:1
Number of Recording Pixels	RAW High: T: 5424 x 3616; M: 2712 x 1808; B: 2712 x 1808 Low: T: 2704 x 1808; M: 2704 x 1808; B: 2704 x 1808 JPEG 21:9: Super-High: 7680 x 3296 High: 5424 x 2328 Low: 2704 x 1160 16:9: Super-High: 7680 x 4320 High: 5424 x 3048 Low: 2704 x 1520 3:2: Super-High: 7680 x 5120 High: 5424 x 3616 Low: 2704 x 1808 4:3: Super-High: 6816 x 5120 High: 4816 x 3616 Low: 2400 x 1808 1:1: Super-High: 5120 x 5120 High: 3616 x 3616 Low: 1808 x 1808
ISO Sensitivity	Auto (high and low limits); ISO 100-6400 (in 1/3 EV steps)
White Balance Modes	Auto, Auto (Lighting Source Priority), Daylight, Shade, Overcast, Incandescent, Fluorescent, Color Temperature, Flash, Custom
Color Modes	Standard, Vivid, Neutral, Portrait, Landscape, Cinema, Sunset Red, Forest Green, FOV Classic Blue, FOV Classic Yellow, Monochrome
Autofocus Type	Contrast-detection type
AF Points	9 points (selectable), Free move mode, Face detection AF
Metering Systems	Evaluative Metering, Center-Weighted Average Metering, Spot Metering
Exposure Control Systems	Program AE (Program Shift possible), Shutter-Speed Priority AE, Aperture-Priority AE, Manual
Exposure Compensation	+/- 3 EV in 1/3 steps
Shutter Speed Range	30 to 1/2000 sec.
Drive Modes	Single, Continuous, Self-Timer (10 or 2 sec.), Interval Timer
LCD Monitor	3.0" 920k-dot TFT-LCD
Interface	USB, Cable Release Switch
Power	BP-51 rechargeable lithium-ion battery pack

Comparison Chart

	dp1 Quattro	dp2 Quattro	dp3 Quattro
Focal Length (35mm Equivalent)	19mm (28mm)	30mm (45mm)	50mm (75mm)
Aperture Range	f/2.8 to f/16	f/2.8 to f/16	f/2.8 to f/16
Number of Diaphragm Blades	9	9	7
Lens Construction	9 elements in 8 groups	8 elements in 6 groups	10 elements in 8 groups
Focus Range	7.9" / 20 cm to infinity; LIMIT mode	11" / 28 cm to infinity; LIMIT mode	8.9" / 22.6 cm to infinity; LIMIT mode
Maximum Magnification	1:8.3	1:7.6	1:3
Dimensions	6.4 x 2.6 x 3.4" / 161.4 x 67 x 87.1mm	6.4 x 2.6 x 3.2" / 161.4 x 67 x 81.6mm	6.4 x 2.6 x 4" / 161.4 x 67 x 101.8mm
Weight	Not specified by manufacturer	13.9oz / 395g (without battery or card)	Not specified by manufacturer