The Sigma DP1 Merrill ($999 direct)($648.00 at Amazon) is the latest iteration of the company's ground-breaking DP1, which, back in 2009, was the first digital compact to squeeze a D-SLR sized APS-C image sensor into a pocketable body. The market is a bit more saturated now, with competing models like the Leica X2($1,000.42 at Amazon) and the full-frame Sony Cyber-shot DSC-RX100($369.99 at Dell). The DP1 Merrill sets itself apart from the crowd with a wide-angle (28mm equivalent) lens and a Foveon image sensor, but it's a camera that requires some work and patience to really appreciate. If you're a more casual shooter, you're better off with our Editors' Choice, the Sony RX100, a pocket shooter with a smaller, but top-notch, 1-inch image sensor, and a lower price.

Foveon Image Sensor, Design, and Features

Much like the Sigma SD1 Merrill($500.00 at Amazon), the DP1 uses a Foveon X3 image sensor. This design uses three layers to record information, each one sensitive to a different color channel. Traditional digital cameras use a single-layer sensor with a Bayer overlay, which has grids of red, blue, and green pixels to create a color image. Each layer of the DP1's sensor boasts a 15.4-megapixel resolution—because of this, Sigma advertises it as a 46-megapixel camera, even though the resulting, printable images are limited to 15.4 megapixels in size.

The sensor design omits the low-pass filter, which is a trend on higher-end cameras. But because of its design, which by its nature omits the Bayer color-array filter, there's no danger of moiré entering into your shots. The downside to the unique design is that there's no support for the DP1's Raw format in Lightroom or similar software programs—you'll have to use Sigma's Raw software to process photos.

In terms of design, the DP1 is essentially a brick with a lens, measuring 2.6 by 4.8 by 2.5 inches, and weighing in at 12 ounces. It's not that far off in size and weight from the 2.7-by-4.9-by-2 inch, 11.2-ounce Leica X2, which has a narrower 36mm-equivalent lens. The X2 supports an add-on EVF, which is an option that is not available on the DP1. There is a hot shoe directly above the lens, so using a fixed optical finder that matches its field of view and trusting its autofocus system is an option.

The lens is a 19mm focal length, which translates into 28mm in terms of full-frame photography. It has a maximum aperture of f/2.8. The field of view is the widest of all of the current fixed-lens compact cameras. (Sigma also makes a DP2 Merrill with a 46mm equivalent lens, and a DP3 Merrill with a 75mm, each with a maximum f/2.8 aperture.) If you're looking for zoom, look elsewhere, but for those of us who see the world in that focal length, the DP1 is a welcoming camera.

Pleasingly minimal, the camera's color scheme is flat black, with a metal chassis that is cool to the touch. Buttons are labeled in white—for shooting functions—and red—for playback functions. On top you'll find Power, Mode, a control wheel, and the shutter. The rear houses the Auto Exposure lock, a four-way controller with a center select button (the up direction lets you select the focus mode, the bottom the focus point), Play, a button to control the amount of information shown on the rear display, a Menu button, and the QS button.

The QS (Quick Set) button grants access to seven quick shooting controls. Press it once and you can adjust the ISO, Exposure Compensation, Drive Mode, and image format settings. Press it a second time and the menu switches to White Balance, image compression, color balance, and image format (in the same place as the first menu) settings. It's a well-designed interface, and lets you adjust settings without diving into the menu system.

The 3-inch rear display packs a 920k-dot resolution. It's sharp and gives you a good idea about the quality of the images you are capturing—although if you're shooting at higher ISO settings, the JPG previews that are displayed will look downright awful compared with the Raw files that the DP1 can capture.

Performance, Workflow, and Conclusions

Performance, Workflow, and Conclusions

The DP1 isn't a fast camera, but it's not terribly slow when compared with the other big-sensor compacts that we've tested. It starts and shoots in about 2.9 seconds, records a 0.3-second shutter lag, and can fire off a short burst of shots at about 3.8 frames per second. The Canon PowerShot G1 X starts in 2.5 seconds, but notches a longer 0.4-second shutter lag and can only shoot at 1.7 frames per second.

Where the DP1 slows you down is burst recovery time. It can rattle off 7 shots before its buffer fills, but it will take a good deal of time to write those to the memory card—32.7 seconds for JPG, and about 45.5 seconds for Raw or Raw+JPG. You can take another photo after the first has cleared, so you'll be locked out of shooting for about 5 seconds after a full JPG burst or 6.5 seconds for Raw+JPG. A SanDisk 95MBps memory card was used to perform the speed tests. In terms of focus speed, its 0.3-second shutter lag accounts for a focus confirmation and shot in good light, but it slows to about 0.6-second if it needs to rack into focus. In dim light the focus speed dips to a respectable 1.8-second.

I used Imatest to check the sharpness of the camera's JPG output at its base ISO setting of 100. Images were incredibly sharp, registering 2,162 lines per picture height at f/2.8; 1,800 lines is our cutoff for an acceptably sharp photo. Stopping down to f/4 increases the resolution to 2,513 lines, and quality doesn't suffer until you get down to f/8, where the score dips to a still impressive 2,360 lines due to diffraction. The Leica X2, while sharp, only manages 2,089 lines at f/2.8.

Imatest also measures noise, which robs detail and makes images look grainy when it crosses the 1.5 percent threshold. When shooting JPG photos with the DP1, noise quickly becomes a problem. It makes up 1.6 percent of an image at ISO 200, and increases to 2.7 percent by ISO 400. If you convert Raw images to TIFF using Sigma's Raw converter, noise is less of an issue. It is controlled through ISO 800, and can be further curbed by adding a little bit of noise reduction prior to conversion. If you're looking for a compact camera with a big sensor that does well at the highest ISO settings, consider the svelte, zooming Sony RX100—it keeps noise in check through ISO 6400.

Because of the ISO issues when shooting JPG, this is really a camera that you'll need to use in Raw mode for best quality. Normally this wouldn't be a major black mark, but because the Foveon sensor design is unique to Sigma cameras, only the Sigma Photo Pro application supports the format—and that software leaves a lot to be desired in terms of editing. The Sigma software isn't the most intuitive, is rather slow, and lacks a lot of the finer editing features—including degree-by-degree rotation, spot correction, and graduated filters—that are available in Lightroom. You'll need to devote quite a bit of storage space using this method—each Raw file is around 50 megabytes and a 16-bit TIFF is closer to 90MB in size—that's 140MB per shot.

When properly processed, you can pull an incredible amount of detail out of the Raw files—see the slideshow for an image and a 100 percent crop that demonstrate what the DP1 Merrill is capable of, even at a slower shutter speed and at ISO 800. If you capture a high volume of images and rely on batch Raw processing tools—or JPG shooting—to speed your workflow, the DP1 will likely frustrate you. But if you tend to spend a good amount of time perfecting each photo, the camera will better suit your style.

You'll have to learn the how to best process your files to appreciate them, and you'll still deal with a few quirks of the Foveon design. The red channel is especially prone to clipping, but you can dial down contrast just a little bit in Sigma's software in order to prevent this from happening. In order to get the best results from the DP1, Sigma's engineers recommend that you set Sharpening to -1 or -1.5 in Sigma Photo Pro, and later apply sharpening in Lightroom. They also recommend dropping color saturation down one or two notches, and to set noise reduction at its lowest for photos shot at ISO 100 or 200, but to leave it in its default setting when shooting at higher ISOs. This methodology was followed for the sample images in the slideshow.

The DP1 Merrill can record video, but it's not where this camera excels. Resolution is limited to 480p30 in AVI format, and the internal microphone is pretty quiet compared with others. The footage lacks any pop in terms of color, and it shows some evidence of the rubber pencil effect, likely a result of the rolling shutter effect, during pans—the top of the frame will pan ahead of the bottom.

The only data connection on the camera is a proprietary interface that carries USB and video output using included cables. Standard SD, SDHC, and SDXC memory cards are supported.

To say that the Sigma DP1 Merrill is not for everyone is an obvious statement. If you're a casual snapshooter who simply wants a point-and-shoot camera that produces excellent images, you'll want to take a close look at the Sony Cyber-shot DSC-RX100—its 1-inch image sensor and zoom lens are better suited to the task. But if you are serious about photography, keen on the advantages of the Foveon sensor, and willing to live with the workflow that goes along with it, the DP1 Merrill is an appealing camera. It's also the only one of its class to offer a 28mm equivalent prime lens—the Fujifilm X100s, Leica X2, and Sony RX1 all opt for the narrower 35mm field of view—although there is a wide-angle adapter available for the Fuji that opens up its field of view to match that of the DP1 Merrill. So, yes, the DP1 isn't a crowd-pleasing camera; and those who do see the appeal of the camera will have to live with its limitations and put forth the time and effort required by it.

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