Compact Digital Cameras

Place the new Sigma DP2 next to the DP1, its groundbreaking predecessor (which remains in the line) and the resemblance is uncanny. Not only do they look alike, they’re almost exactly the same size. Turn them on, and extend their lenses, and the main difference is immediately apparent—the DP2’s 24.2mm f/2.8 lens (equivalent to 41mm in the 35mm format) is larger in diameter and extends about a half inch farther than the 16.6mm f/4 (28mm equivalent) lens on the DP1.

Inside the DP2’s attractively understated body is the same unique consumer D-SLR-sized (20.7x13.8mm), 14-megapixel Foveon X3 sensor that’s used in the DP1 and in the Sigma SD14 and SD15 D-SLRs. The other thing that hasn’t changed is the basic DP design concept: it is a robust, elegantly compact camera of elemental simplicity fitted with a very high-quality single-focal-length lens and a big sensor. It’s an unobtrusive no-frills camera in its simplest and purest form that claims to be optimized for image quality. Whether this radically minimalist idea makes sense in a world populated by more affordable high-performance zoom point-and-shoots with similar megapixel ratings, interchangeable-lens EVF compacts, and a welter of enticing, similarly-priced D-SLRs that seem to offer more for your money is an open question.

Classic Landscape

Taken at Arches National Park in Utah, this shows excellent detail, subtle color differentiation, and very good depth of field. All Photos © 2009, Jason Schneider, All Rights Reserved

The most obvious difference between the DP1 introduced in March 2008 and the new DP2 is the lens. The DP2 incorporates a multi-coated seven-element, six-group 24.2mm f/2.8 lens with two molded glass aspherical elements that provides a 35mm-equivalent focal length of 41mm. This is close to the diagonal of the 35mm format (43.3mm) and therefore falls within the normal focal-length range (about 40-60mm). Significantly, the DP2’s lens is one full stop faster than the 28mm wide-angle equivalent (16.6mm f/4) lens fitted to the DP1, offering advantages both in low-light shooting and when using shallow depth of field to diffuse the background and draw attention to the main subject.

This shot taken at Arches National Park in Utah shows excellent definition at point of focus (flowers) with smooth sharpness falloff in foreground and background.

Upgraded Features
Sigma’s new TRUE II image-processing engine is probably the most significant performance upgrade in the DP2 because it affects image-processing quality and speed. Based on “proprietary algorithms,” TRUE II enhances color reproduction and dynamic range, providing noticeably better performance at higher ISOs than the DP1. For the record, the DP2 has ISO settings from 50-800 for all file sizes, and offers ISO 1600 and 3200 in raw capture. TRUE II also claims to enhance the camera’s overall performance parameters, including automatic exposure, autofocus, white balance, and shutter-response time.

The DP2’s controls have also been improved with larger, better positioned, more clearly labeled up-down buttons, a new QS button that makes it much easier to access frequently made camera settings, and revised menus that are more intuitive and user-friendly. To display the basic camera parameters menu, including LCD brightness and contrast settings, turn the mode dial to SET UP. To display the comprehensive shooting and playback menus set the camera for Capture or Playback mode and press the MENU button. In all, the DP2’s controls and menus are more logical and intuitive than those on the DP1 and we found them more convenient than those in many other enthusiast-aimed compact cameras.

Close-Up Portrait	Farmer’s Market Vignette
The DP2’s semi-wide 41mm-equivalent lens works well in capturing informal close-up portraits with crisp definition and little apparent perspective distortion.	This grab shot of apple baskets in Catskill, New York, was precisely composed on the DP2’s modest-sized (21⁄2”) LCD. Setting the monitor for enhanced brightness and contrast helped in framing the image.

A First-Rate Prime Lens
Virtually all other compact digital cameras have built-in zoom lenses with focal-length ratios ranging from 3x to 12x and beyond. Even the Olympus E-P1, arguably the DP2’s closest competitor, offers a 14-42mm zoom as its standard lens. What then is the theoretical and practical rationale for the DP2’s non-interchangeable, semi-wide 24.2mm f/2.8 (41mm equivalent) lens? Undoubtedly it’s one of the main reasons the DP2 can be fetchingly compact, considerably smaller in fact than the aforementioned Olympus E-P1. And while a prime lens is undoubtedly less convenient and versatile than a zoom, it’s an optical fact of life that single-focal-length lenses of moderate aperture are among the sharpest lenses available, because they have fewer aberrations to begin with and are easier to correct to the highest standards of imaging performance. Sigma has taken advantage of these characteristics in designing an ultrahigh-performance seven-element, six-group lens of retrofocus design that employs large-diameter molded glass aspherical elements, a configuration typically found only in high-end interchangeable lenses for D-SLRs and rangefinder cameras.

In our field tests, we confirmed that the DP2’s 41mm-equivalent f/2.8 lens delivers very low field curvature and astigmatism, providing superb sharpness from the center to the corners of the image field even wide-open. It also stops down to f/14, a smaller minimum aperture than that found on most compact digital cameras, and maintains its performance at all apertures and distances down to 11”.

ISO Performance Comparison

ISO 50

ISO 3200

At ISO 50 the DP2 delivers topnotch definition and overall image quality along with very good color. This level of performance is maintained at ISO 100 and 200. At ISO 3200 definition is marginal with considerable “digital grain” and muddy color rendition—not acceptable for most purposes. However, the DP2 performs very well at ISO 400 and reasonably well at ISO 800.