Sigma dp2 Quattro Optics

30mm fixed focal-length lens
Superb performance from the 30mm (45mm equivalent) lens.

The Sigma dp2 Quattro is equipped with a 30mm f/2.8 fixed lens, with a 35mm equivalent focal length of approximately 45mm. Construction consists of 8 elements in 6 groups, with a 9-bladed diaphragm providing a minimum aperture of f/16.

Sharpness and contrast are outstanding across the frame at f/8, with no signs of coma distortion and just a touch of chromatic aberration visible towards the corners and edges of the frame. Truly superb performance in our Far-field test.

Macro
A much larger-than-average macro area, with good detail.

The Sigma dp2 Quattro captures a much larger-than-average minimum macro area measuring 6.78 x 4.52 inches (172 x 115 millimeters). Detail is good, though, and corners are sharp when stopped down to f/8. (Most lenses have some softening in the corners at macro distances, so the dp2's lens performs quite well in this regard.)

Geometric Distortion
Low barrel distortion.

The Sigma dp2 Quattro's lens produces about 0.4 percent barrel distortion; which is fairly low and just slightly noticeable in its images. And the camera does not apply geometric distortion correction to JPEGs. This is the tendency for the lens to bend straight lines outward (like a barrel -- usually at wide-angle) or inward (like a pincushion -- usually at telephoto).

Chromatic Aberration, Corner Sharpness & Vignetting
Low chromatic aberration with outstanding corner sharpness, though some vignetting.

Chromatic Aberration. Chromatic aberration is low in the corners with fairly dim and narrow red/blue fringing wide open or stopped down, and the camera does not appear to be suppressing CA in JPEGs. (This distortion is visible as a slight colored fringe around the objects at the edges of the field of view on the resolution target.)

Corner Sharpness. The dp2 Quattro's lens produces sharp corners wide open, with only very minor softening, and the center is very sharp wide open. Corner sharpness stopped down to f/8 is about the same as the center, which is to say excellent.

Vignetting. A moderate amount of "vignetting" (corner shading) is visible when wide open, as can be seen from the darker corner crop at f/2.8 (top left). A small amount of corner shading still occurs when stopped-down to f/8, but it's almost negligible and easily correctable.

Bottom Line: A fantastically sharp lens from corner to corner, with only minor distortion and moderate vignetting wide open, though macro performance isn't great.

Coverage
Excellent accuracy from the LCD monitor.

The Sigma dp2 Quattro's LCD monitor showed essentially 100% frame coverage in our test, which is excellent.