Sigma DP1 Overview
by Shawn Barnett
Review Date: 05/01/08
The Sigma DP1 was designed for anyone wanting digital SLR quality in a small package. Starting with the Sigma DP1's sensor, Sigma chose Foveon's 14.1-megapixel sensor that outputs a 4.64-megapixel image. Each of those pixels is created by three photosites that are stacked in layers, recording full color information at every pixel location. The maximum resolution is identical to that of Sigma's SD14 digital SLR: 2640 x 1760 pixels (uninterpolated), with a 3:2 aspect ratio. (Traditional Bayer-sensor cameras capture only one color at each pixel location, and interpolate the other two colors from surrounding pixels, leading to somewhat reduced luminance resolution, and a significant reduction in chrominance resolution and other color-related problems).
The Foveon X3 image sensor is coupled to a 16.6mm lens with a focal length crop equivalent to a 28mm lens on a 35mm camera. The lens has a maximum aperture of f/4. Keeping lens size and weight down for a compact camera that uses a sensor not much smaller than those used in most digital SLRs must have proved quite a challenge, and the lack of an optical zoom and maximum aperture limitation hint at this. The Sigma DP1's lens also supports manual focus via fly-by-wire.
There's no optical viewfinder on the DP1, but Sigma offers an optional external viewfinder that mounts in the flash hot-shoe. Images can however be framed on the 2.5-inch LCD -- the same size as is used in the SD14. While there's no optical zoom, the Sigma DP1 offers a 3x digital zoom. In addition to the dedicated flash hot-shoe, there's also a popup flash on the top of the camera.
The Sigma DP1 also offers a 320 x 240 pixel, 30 frames-per-second movie mode. Other modes on offer in the Sigma DP1 include auto, program, aperture-priority, shutter-priority, manual, and an audio recording mode. Finally, there are controls for exposure compensation, and auto-exposure locking, plus for the flash and a macro mode. The Sigma DP1 offers both X3F RAW (12-bit) and JPEG image recording modes.
The Sigma DP1 is available for about US$799.
Sigma DP1 User Report
by Shawn Barnett
Just about every photography aficionado I know is keeping their eyes open for the ideal, high-quality camera to bring along when they don't want to carry an SLR. Certainly most of us here at Imaging-Resource.com headquarters consider carefully each unique camera that turns out decent images and slips into a pocket. The Sigma DP1 raised eyebrows and expectations two years ago, and once it arrived this year it got a closer look than most non-SLR digital cameras.
Sets of criteria vary by individual, but the general desire is for a small to medium-sized camera with a fast, good quality lens, and an excellent sensor that rivals an SLR. This used to be much easier to achieve when the sensor was a roll of film. Many photographers carried something like an Olympus Stylus or XA, or small rangefinder, each of which used the same film a 35mm SLR held.
Most small digital cameras, however, use sensors that are smaller than a thumbnail, have tiny pixels that are prone to high noise even in bright sunlight, and use small optics, insufficient for an APS-C-sized sensor.
Some of us have settled for the Canon G9 with its f/2.8 lens, 1/1.8 sensor, and RAW image recording; but most still want something smaller, with a better lens (the G6's lens would do), and a larger sensor. I carry a small SLR with a prime lens, and a smaller, pocket point-and-shoot digital camera for stills and video, but would still take an interest if the right camera came along.
So the question is, how does the Sigma DP1 do compared to our list of desires? How will it do for you?
The short answer is that it takes great wide-angle pictures if you take the time to work at it and get to know the Sigma DP1. Further, you need to have the time to wait for the Sigma DP1, as well as its software, to get the best quality from the camera. You also have to be content with the lower resolution on the Sigma DP1. Though it technically has 14.1 megapixels, you have to divide that figure by three to get the actual image size, which is a very smooth 4.69 megapixels; the actual images measure 2,640 x 1,760, or 4.646 megapixels.
Each pixel of each resulting image is made up of three pixels, stacked in layers much like film. It's been about two years since we reviewed the last 4-megapixel digital camera, so it's very strange to have to compare the Sigma DP1's 2,640 x 1,760 images to images from more modern cameras, especially the SLRs that it is supposed to rival. But more on that toward the end of the review.
Look and Feel. The Sigma DP1 is a handsome digital camera, with an air of confidence. Its no-nonsense allure diminishes somewhat when you press the power button, extending the aardvark-like snout of a lens to its proper 16.6mm focal length (equivalent to a 28mm lens on a 35mm camera); an operation that makes quite unusual sounds and takes a long time.
Gripping the Sigma DP1 is comfortable and natural, and a series of bumps on the front and back panels offer just enough assistance, as well as a good tactile indication of where your fingers are on the DP1. The index finger finds the flat shutter button naturally, and the thumb finds a reasonable resting place on the back, just above the Four-way navigator. I did accidentally change focus methods with my thumb when hand-holding the Sigma DP1, but not too often. The buttons are firm, giving reassuring feedback with each press.
Button placement is good, with the AEL and EV adjustment buttons just left of my thumb's resting place. And though the Sigma DP1 has a fixed-focal-length, it does include a digital zoom function, which explains the Wide and Tele buttons just above the thumb grip area.
The Menu button is in the center of the Four-way controller, which brings up an attractive menu with small fonts, but they're somewhat jaggy, and switching between menu screens can be slow.
A springloaded switch upper left of the Sigma DP1's LCD releases the recessed flash to pop up from the camera's top surface. The flash hot shoe on the top has a plastic cover that removes to allow installation of the optional external viewfinder or the EF140 external flash.
The Sigma DP1's simple mode dial selects from the basic exposure options that most aficionados will look for (PASM), plus full auto, video, and audio record modes. Video, unfortunately, only records at 320x240, hardly worth considering.
The shutter button has a mushy travel toward firm resistance that gives with a good click. Despite needing the negative-sounding adjectives to describe the feel, it's actually quite good.
Finally, right behind the Sigma DP1's shutter, we find the enticing manual focus dial. Sounds good, doesn't it? Unfortunately, although there's an artificial audible click and an onscreen scale, it's really hard to focus with any accuracy on the 2.5-inch LCD screen. There is a digital zoom to aid in focusing (which I only found after posting the review, thanks to a forum poster), that works fairly well, though it's still hard to determine an exact point of focus. There's also no focus confirmation for reassurance when focus has been achieved. However, if you just want to lock the Sigma DP1's focus at infinity, it's a long turn to the right; and if you want to set a distance you can measure with a yardstick or two, you can choose from 57 steps on the LCD's scale, as opposed to the 17 on the dial's scale.
A rubber door covers the Sigma DP1's DC-In and USB/AV ports. It's a little difficult to remove but is consequently snug.
The battery and card door on the bottom plate opens with a slide to the right, revealing the Sigma DP1's SD card slot and the BP-31 lithium-ion battery, which is held in place with a white latch. Though the battery life is not great, rated at around 250 shots, batteries are available for $20 online, so there's no reason not to buy at least one spare.
The Sigma DP1's tripod socket is metal, held in place by three screws in the Sigma DP1's two main metal shells.
Lens. The Sigma DP1's lens is of good quality, with minimal chromatic aberration and remarkably little distortion. As I mentioned, it comes out slowly to its fixed position and doesn't move when focusing.
Unless you buy and use the optical viewfinder ($149), the Sigma DP1's LCD is your only method of framing your images. The optical viewfinder is nostalgic, and does provide a way to generally point this wide-angle lens at your subject, but is not great for framing images. The silver framing guide inside the optic doesn't appear most of the time indoors, and a good deal of the optic is blocked by the optional lens hood.
Also priced under $20, the lens hood is a good accessory to buy, but it does make the camera a lot bigger out front, destroying the Sigma DP1's pocketability. And unfortunately, the camera's lens cap does not attach to either part of the two-piece lens hood, leaving the lens exposed to dust, dirt, and physical damage. No cap is included with the lens hood.
The lens cap itself is pretty solid, having no moving parts, and offering good protection for the lens; but annoyingly it has to be attached in a horizontal orientation, with the logo upright or upside down. There is no tether.
Digital zoom. Though the Sigma DP1 has a fixed-focal-length lens, it also features eight levels of digital zoom, up to 3x, or roughly equivalent to a 72mm lens on a 35mm camera. But you can't focus well at all in this mode, because you're presented with a terribly jaggy live image. The digitally zoomed image itself is also soft and jaggy, because it's upsampled to the full sensor resolution of 2,640 x 1,760.
Interface. I've described the buttons as well-placed and of good quality, but the camera's interface could use some help. Commonly used items like ISO, Drive mode, and AF area are only adjustable via the Sigma DP1's Shooting menu. The last item in particular needs addressing, because though you can select from nine autofocus points, you have to scroll down eight times, and wait for the animated menu display to scroll to the second screen before you can select an alternate AF point. Even on a tripod, I found this to be a particular nuisance.
Given the few controls on the DP1, Sigma had little choice. The up arrow is used to set the Focus mode, and the down arrow cycles through the flash modes. The right and left arrows, though unlabeled, serve as Program Shift buttons when in Program exposure mode; in Shutter and Aperture priority modes, they adjust the shutter or aperture setting; in Manual mode, they adjust either setting again, switching between the two with the EV compensation button; and in all other modes, they do nothing.
Some with limited near vision might find the Sigma DP1's small menu fonts hard to read, but I didn't have a problem with them. The white fonts are outlined with gray, so that you can read them better against a white background.
Modes. I started using the Program mode and using EV compensation to bracket my exposures, but had better results in Manual mode. As Sigma's literature asserts, you get better results with the DP1 when you think, paying attention to what you're trying to achieve, rather than just trusting the auto modes to do the work for you.
There's really not a heck of a lot to say about the modes, except that the basic Auto, Program, Shutter, Aperture, and Manual are present. As for metering modes, because the Sigma DP1's matrix metering didn't seem to be understanding some of my scenes, I switched to Center-weighted metering, which worked better for me. Your results will vary.
Performance. The Sigma DP1 is the slowest camera I've used in recent memory. Powering it up takes 3.9 seconds, and full autofocus and image capture takes 1.53 seconds. With a single focal length, this really should be faster. As I've already mentioned, changing autofocus points on the DP1 is painfully slow, so all basic aspects of taking pictures with the Sigma DP1 are slower than film, and slower than digital.
Saving an image to the card is also tough to deal with. I made the mistake of taking a Class 2 SDHC card on an outing with the Sigma DP1, and started to lose interest in taking pictures with the tripod-mounted camera, as I had to wait 15 seconds for the RAW images to save off to the card. And the camera didn't make the wait easy, either. While it's saving data off to the card, you can't adjust anything. So I couldn't change the Sigma DP1's EV compensation, aperture, or shutter setting while I waited for the save to complete. I just had to wait and watch the red light flash. One RAW image saves more quickly with a Class 6 SDHC card, but it's about nine seconds from start to finish; add that I was using a 2-second self-timer, and it's still a long time to bracket. The process is made longer because the Sigma DP1 takes a few seconds to process and show you the image on the LCD before it even begins saving it to the card.
Of course, you can use the Sigma DP1's auto bracketing mode, which allows three rapid shots, separated by up to 3.0 EV, but this still takes 16 seconds to save the images to a Class 6 card. (I was doing a more detailed bracket with more steps.) At least you can get three shots off rapidly without a lot of fiddling.
Software. The bundled Sigma Photo Pro RAW processing software is good and bad. I like how you can either install it on your machine, or run it from the disk (at least on a Mac). It's also a pretty straightforward RAW processing engine that's easy to understand and use. What's disappointing is again the speed. From building thumbnails to making even a minor adjustment takes a long time. I felt a lot like I did when I was out in the field, getting bored between adjustments, feeling like I was missing other opportunities while I waited for the program to apply my tweak.
I used the default conversion settings to create JPEGs of our RAW test images, and aside from oversharpening a bit, the results are pretty nice. More consistent than some of our JPEG shots. Clearly if you want the best from the Sigma DP1, you need to shoot RAW and process images in this application. Just make sure you have a lot of time, and a very fast computer.
Image Quality. When I got back to the office to look at my images, I was glad I'd bracketed, and surprised at which images were the good ones. Images that looked badly underexposed out in the daylight were actually about right. Focus, however, was all over the place. Some shots that I thought were fine were far from it. Many of the f/4 shots were softer than I could see on the Sigma DP1's LCD.
Color was flat, but detail in the well-focused images was surprising. Though the images aren't large, only just exceeding the size of most of my computer screens, the detail is -- not crisp, that's just the wrong word -- but smooth. They look a little more real, like you could reach out and touch the image and feel texture. However, it's hard to overlook the smaller size of the image. Had this sensor been introduced three years ago, I think we'd be looking at a very different sensor marketplace today. It's as if someone took the four-megapixel sensor and kept working on it until it reached its full potential.
Shooting. I really expected to enjoy my outings with the DP1, but I found that exploring the tripod-mounted world of the Sigma DP1 to be too slow. Moving around with and adjusting a tripod is already slow enough, but add a slow camera and it gets frustrating. Still, I like shooting handheld with a wide angle lens, and when just taking single shots, the Sigma DP1 was fun to use.
I discovered that the Sigma DP1's fake click sound that plays when you trip the shutter is just about the exact moment of capture, rather than the softer click you hear from the shutter button itself. That there's a delay between the two clicks is no surprise, but that the audio is spot-on is good to know.
Because the LCD is hard to read for both exposure and focus, I felt like shooting with the DP1 was a bit like throwing a Hail Mary pass; you just shoot and pray you did it right. I often had to shoot from high or low angles to adjust for the Sigma DP1's perspective distortion, which made framing images on the non-articulating LCD screen with the shiny reflective screen cover even more difficult.
And because my photographic eye is used to being able to zoom or switch lenses, I was often disappointed when the Sigma DP1's lens couldn't crop the way I wanted. Used to zooming with my feet, I'd try to frame an image from a certain distance, then walk forward to reframe a little tighter. But then the 16mm lens distorted the scene such that I no longer wanted the shot. The lens couldn't deliver what I had seen from a distance. I needed a different lens. It's not really a flaw with the camera, just a limitation I'm not accustomed to.
Though it's not a big deal when shooting still life on a tripod, the Sigma DP1's AF system freezes the screen for between a second and a half-second while it's focusing, long a pet peeve of mine. That makes the camera less useful for people or any type of action picture. As for shots of any but the most sedate kids, forget about it.
Autofocus indoors is unsure at best, and worse at night. Most cameras we test can still achieve focus on a high contrast subject down to 1/8 foot candle, and the Sigma DP1 stopped at just below one foot candle. There is no AF assist lamp.
I also found my shooting both indoors and out limited by the Sigma DP1's f/4 to f/11 aperture range. The shutter speed range is a little broader, going from 15 seconds to 1/2,000 second. But it helps to think in a third exposure dimension and adjust the ISO. When shooting RAW, the high ISO images from the Sigma DP1 are quite impressive, even up to the maximum ISO 800. The lack of a histogram while shooting is a significant omission, considering the difficulty I had judging exposure on the LCD, especially while shooting outdoors. There is a histogram available in Playback mode, but it takes too long to get there, especially when shooting RAW.
Appraisal. Such mixture of excellence and sub-standard performance make evaluating the Sigma DP1 difficult. It's hard to discount the smooth beauty of the DP1's output, thanks to both the well-designed Sigma lens and the refined output of the Foveon X3 sensor. But the slow autofocus, difficult interface, and slow post-processing required to achieve that excellence is hard to ignore. To be sure, the Sigma DP1 is not a good choice for the casual shooter; and JPEG shooting is really a bad idea. Its current lack of accessory lenses also makes the Sigma DP1 tough to recommend to most photographers looking for a small, light, multi-purpose digital camera. But for those looking for a particular vision, a single, unique way of making photographs with a wide-angle lens, the Sigma DP1 is worth a look.
As I went over my images, I was struck by the detail and lifelike quality of the most mundane images, and I took a moment to scribble this line into my notes: "If you want to bring home everything you see so you can look at it later, the Sigma DP1 is a great choice."
Sigma DP1 Basic Features
- 14.1-megapixel Foveon X3 sensor, a three-layer design outputting a 4.64-megapixel, 2,640 x 1,760 image
- 16.6mm f/4 Sigma prime lens, equivalent to a 28mm lens on a 35mm camera
- 2.5-inch LCD
- ISO 100 - 800 sensitivity
- 15 - 1/2,000 second shutter speed
- SD/SDHC memory card compatibility
- Lithium-ion battery
- Pop-up flash
- Basic PASM exposure modes
- 320 x 240 Movie mode
- 4.5 x 2.3 x 2.0-inches (113 x 60 x 50mm)
- 9.8 ounces (278g)
Sigma DP1 Special Features
- APS-C sensor on a small camera
- Each image pixel is made up of three special photosites designed to capture individual data for each color: Red, Green, and Blue
- Small size
- Hot shoe for optional flash
- 3x digital zoom
- Bracketing mode
- RAW capture option
In the Box
The Sigma DP1 ships with the following items in the box:
- Sigma DP1
- Lens cap LCP-11
- Neck strap NS-11
- Lithium-ion battery BP-31
- Battery charger BC-31
- Soft case CS-70
- USB cable
- A/V cable
- Sigma Photo Pro disk
- Instruction manual
Note: No SD or SDHC card is included.
- Large capacity SDHC memory card. Be sure to get a 4 to 8GB, Class 6 SDHC card, or card writes will be annoyingly slow
- Spare BP-31 Lithium-ion battery
- Sigma EF-140DG flash
- Rechargeable AAA batteries (for flash)
- Sigma Hood Adapter HA-11
Sigma DP1 Conclusion
Sigma's DP1 was long awaited by camera aficionados, especially those looking for an affordable "second camera" that's small enough to bring along, but captures images of SLR quality. While the DP1 exceeds expectations of image quality relative to its 4.6-megapixel image size, it falls short of current speed and operational standards, making it difficult to use for most who are accustomed to other modern digital cameras. Sigma's statements in their brochure that too many cameras have automatic features that take some of the art out of photography have merit, but that doesn't apply to making basic items like Drive mode and AF point settings easy to access, nor does it apply to adjustment of camera controls while images are saved to a memory card. If photographers are going to have to compromise on overall image size, it's a lot to ask to have them compromise on functionality as well.
But the flip side is that the Sigma DP1 has two of the most important elements that make a camera useful: an excellent lens and an unusually good sensor of sufficient size to reduce image noise and deliver surprisingly good photographs. The Sigma DP1 is not a great people camera thanks to the 16mm wide-angle lens, but it is an interesting solution for landscape and other scenic photography. Its very low barrel distortion numbers mean that the Sigma DP1's lens is a great choice for shooting objects with straight lines. Of course, the usual perspective distortion still applies, so it can be difficult to choose a good point of view with the DP1; but that's part of the fun. Finally, the Sigma DP1's printed results prove that RAW images can produce good quality 11x14-inch prints from ISO 100 to 800.
Thanks to its higher price of around $800 and the other limitations mentioned above, the Sigma DP1 doesn't meet the needs of the general photographer wishing for an SLR replacement or substitute. However, the patient photographer might find the Sigma DP1 a refreshing pocket companion for wide-angle photography, and it would certainly serve well as an auxiliary wide-angle choice while shooting with a telephoto lens mounted on your SLR -- if only it were a little faster. As with any photographic tool, an artist can make much of any device that can image as well as the Sigma DP1.