Sigma SD9
Digital SLR With Unique CMOS Chip

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Sigma SD9

These colorful socks sat in a stall in bright sunlight. Opened in the Sigma Pro software, an adjustment was made to keep the highlights under control and slight color saturation was added, even though the color was bright and rich even without work.
Photos © 2002, George Schaub, All Rights Reserved

The long-awaited Sigma SD9 Digital SLR arrived in our offices and although we had a brief hands-on shoot with it during photokina last September this was our first opportunity to put it through its paces. First off, the SD9 is the one and only digital camera thus far to sport the Foveon X3 sensor. The sensor works with a unique three-layer capture area that differs from the more common checkerboard "filter" setup used in most other sensors. We have covered this in depth previously, so we won't go over this territory again. Although the chip architecture is unique, the proof is in the images and not in the explanation of how the image is formed. But how the image is formed is so integral to making decisions about this camera that it is worth close inspection. The files it produces are proprietary, and there's no option other than shooting in its RAW format. But before we get to that let's take a look at the physical setup of the camera and what it offers.

The Sigma Pro software also allows you to make more marked changes, as seen in this low saturation rendition of the same scene. You can drag the saturation slider all the way to the left to create monochrome renditions, if desired.

The SD9 Experience
The SD9 is designed like most SLRs, but there's some time required to get familiar with all those buttons and dials. Happily, the user's manual is quite comprehensive and thankfully printed in booklet form. The camera body is largish, but not unmanageable, and is covered with numerous user controls, which we'll review shortly. The lens mount is Sigma only, although the company certainly has a full line-up of attractive lenses to offer. We worked with the Sigma 15-30mm f/3.5-4.5 DG lens, which, when you factor in the 1.7 magnification factor (due to the size of the sensor in relation to a frame of 35mm film) turns into an approximately 25-50mm equivalent focal length. When you look through the finder you actually see a mask in the frame, which crops to the sensor's view; it's what some call a sports finder (in that you can see what's coming into the frame from the sides) and although it's certainly different it's easy to adjust to after a while. That mask leads us to believe that Sigma may be planning a full 24x36mm chip in future manifestations of this camera, one where they can use the body and workings and just swap out the mask in the finder. But that's pure speculation on our part.

Electric Blue: Who says New York City never has blue sky? Well, we did juice the blue up a bit by adding some color saturation in the Sigma Pro software, but the delineation of line and the brilliant color and contrast of this scene shows you why we think chrome shooters will love this camera. At times we felt like we had the digital equivalent of Velvia in our hands.

Sigma RAW Mode
The camera takes CompactFlash Type I and Type II cards and records in three resolution levels, from a high of 2268x1512 to the lowest being 1134x756 pixels. The sensor itself offers a 3.43 effective pixel count and records only in Sigma's 12-bit RAW mode. This yields something close to a 10MB file when later saved as a TIFF. While that may seem small (at least these days) from a digital SLR, the image itself has a quality that leads you to believe it comes from closer to an 18MB file. However, when you go to print you may not feel comfortable using a low-res setting on your printer, so re-sampling is required if you want to get beyond an 8x10 size using what we consider the standard 240dpi setting on our Epson printers. And one other note--we reformatted a card after downloading but decided to try to get the images back using PHOTORECOVERY from LC Technology ( This software is great for recovering image files from even formatted memory cards. The software did recover files from the card--but they were from a JPEG shoot from three months back, the last time we used that card, even though we had reformatted the card for use in the Sigma camera. The Sigma RAW files were nowhere to be found.

Brilliant color: Shot on an overcast day with the Sigma SD9 at ISO 100 on Program exposure mode, the richness of color and often startling image detail are a hallmark of the X3 chip. This image was converted "straight" from the Sigma Pro software to a TIFF file.

For those used to having a choice between JPEG, TIFF, and RAW, or at least JPEG and RAW, having only RAW output might seem like an omission, as you must work through the Sigma Pro software to convert to these other formats. Because this is a proprietary format you also must view images through the Sigma software, which can be used with both Mac and PC. Happily, you can download both from the camera (with USB and FireWire) and using a CompactFlash card reader, like the SanDisk 6-in-1 we use. And you can download to any folder and reopen the images later in the Sigma software, or on the road to a CD using a walk-up kiosk, although that kiosk cannot display the files it has downloaded, as it does with TIFF and JPEG formats. If the Sigma software is loaded, clicking on any X3 file format in your hard drive will evoke it.

The X3 chip seems to have an uncanny ability to dig into shadows while it retains very good highlight texture. This black truck's surface shows off all the textural shadow detail one could desire, while the background highlights remain well under control.

Exposure And Image Options
The sensitivity of the chip is ISO 100, with ISO 200 and 400 also available. At ISO 100 you can expose in a shutter speed range of 1/6000 sec to 15 sec, with Bulb recording at ISO 100 limited to 16 sec. At the ISO 200 and 400 settings the slowest shutter speed is 1 sec. Flash sync is 1/180 sec. As with most digital SLR cameras, there's a host of white balance modes, exposure modes, auto-bracketing, and all the features that make this an advanced photographic system. The camera is in itself a smooth operator and doesn't get in the way of making pictures. There's of course no time lag between hitting the shutter button and capturing the image, at least not like the delays encountered with some digicams. It should also be mentioned that the buffer on the SD9 offers close to 2 frames per second (fps) for 6 frames in High-Res mode; 2.4 fps for 14 frames in Medium-Res mode; and 2.5 fps for 30 frames in Low-Res mode. The camera connects with USB 1.1 and FireWire to Mac and PC computers.

(Below) The Sigma Pro software interface makes altering image files and moving and saving images to TIFF or JPEG a breeze. (Above) The tonal and image adjustments available in the Sigma Pro software allow you to massage and spice the RAW image format to taste. Controls are intuitive and previews are almost instantaneous. The shadow and highlight slider are excellent controls that allow you to exploit the full tonal spread recorded on the X3 file. The color wheel at the bottom is where you fix color balance, while the Histogram yields read-outs that help with printing later.

The camera back offers a host of buttons that allow you to control the camera and the digital file setup. One thing missing, however, are the menu items that allow you to control contrast, saturation, and sharpness. This is all done later in the software when massaging the RAW images. So, the time you might save having to peruse menus and make such settings is taken up with post-processing later. We'll get to the software momentarily.

Those buttons and toggle switches allow you to choose the usual camera functions, such as drive mode, AF setup, metering modes, autoexposure lock, auto-bracketing, etc. Happily, there's also a push button/command dial procedure for changing resolution modes and the ISO setup. This makes accessing most of the camera controls easy, as you get used to the setup. The menu, view (review), information, and trash keys are also on the back of the camera, all being accessible digital functions. The menu is more a camera operating system or customization area, and once you set these parameters up you are unlikely to change them. In short, everything you might need to operate the camera--both photographically and, if you will, digitally, is right at hand. It's just that you might need a few minutes to sort them all out, but once you spend six minutes with the camera you'll get it.

Image Quality
Now to the image quality issue. There has been much discussion about how the three-color layer chip would fare next to the standard checkerboard arrangement. The folks at Foveon have done overtime selling everyone on the differences and the quality issue, and while we're all impressed with their accomplishment (which other chip engineers say is no mean feat) it's really what happens when the file hits the monitor where the truth will out. Well, based on the time we had with the camera we'd say that it delivers more than satisfying results. Indeed, it's a rival for cameras with higher megapixel counts and the color, sharpness, and delineation of line and tone was at times startling.

But in this case you can't separate the image from the format. If you're OK with having to view through Sigma software only (that's all that can read the file format, at least for now) and working with conversions when you go into Photoshop or other image-editing programs, then you should be more than satisfied with the images this chip and camera produce. In fairness, most digital SLR cameras these days have RAW mode and it's the one recommended by the makers as delivering the best quality and memory efficiency. Indeed, this RAW-only route may be followed by others soon, although we don't see the JPEG option disappearing right away.

Sigma Pro Software
When you open the Sigma Pro software you will be presented with a host of options including exposure, contrast, shadow detail, highlight control, saturation, and sharpness. In most digital cameras these options are processed, to a degree, in the on-board image processor (when you shoot JPEG or TIFF mode) and there's always some of the camera's information "baggage" that is carried along with the original image file. The advantage of RAW, as those who work with RAW in other digital cameras know, is that you get a "cleaner" file that you can add attributes to later.

The Sigma Pro software is a great place to add these attributes, and the controls are accessible, fairly fast, and show a preview as you work. In some cases the image right out of the camera required little or no tweaking and going right to a TIFF save made sense. We were especially impressed with the way the image delivered highlight and shadow detail in fairly high contrast conditions. The sensor seems to dig into the shadows while retaining highlight texture in scenes that would drive other digital sensors a bit mad. And the colors were bright and lustrous, not unlike the current taste for vivid color and sharp tonal edges. Indeed, there was a character to the images quite unlike what we've seen before, in that the original file was not as "flat" and "soft" as we've noticed in other direct from camera file output in some other SLR systems. So, right out of the box the Sigma image has a leg up, we feel, and should satisfy those photographers who usually shoot chrome film. In many cases any tweaking we did was for taste, and not to fix a deficiency in the delivered RAW file.

Of course, if the image is too vivid you have that saturation control in the software, just as you have a soften option (negative sharpness) and even a shadow and highlight modification step, if desired. The color balance control also works well, with a color wheel asking you to place your bet on the best way to counter any color imbalance. You can go the Auto route, but that's not half the fun.

This is a tough shot for any camera, digital or film. The shoppers in the outdoor farmer's market were backlit on a very bright day. After downloading the image was opened up with the shadow control, with highlights topped off as well. Color balance was adjusted to obtain a more neutral rendition, as the original file was a bit on the cool side.

Making The Choice
As with any proprietary approach to digital, or any other image-making process, there is a choice to be made between gaining the advantages of a clearly excellent chip, camera and software combination with always having to work through a system that is unique to the maker. Sigma is not going to go away from the digital market, as evidenced in the work done on this system. But until plugins for using the Sigma format are developed for commonly used software, and at kiosks and other download sites, you will always have to download the images through the Sigma software to see them. In many cases the download itself will be no problem. The RAW file is just like any other data and can be transferred from the memory card to any media.

But we don't know one digital photographer who will reformat their memory card before they are assured that the downloaded file opens properly. To do this with the Sigma RAW files you will have to use Sigma software to convert them to TIFF or JPEG format before you can re-size, send, and even do image manipulation not offered in the Sigma Pro software. In short, once you sign up by buying into the Sigma system, at least for now, you will always have to salute that one flag. Again, the same goes for other RAW formats from every other digital SLR maker. But there may be times when you might need the facility a straight JPEG or TIFF gives you, being more common formats. Clearly, for the Sigma system to gain wide acceptance both Sigma and Foveon will have to do some proselytizing and make a strong effort to get their format "readable" by other software programs and kiosks alike. Even current versions of image organizers, like ACDSee, are blind to the Sigma format.

In our tests we found that the Sigma SD9 and accompanying software really delivered the goods. We felt that the images right out of the camera were among the best we've seen in terms of vivid and true color, sharpness, and especially when it comes to highlight and shadow rendition. If we went pixel to pixel and resolution to resolution then the Sigma would be our choice for one of the best in its class. But getting a 10MB file from a digital SLR these days, especially with the (albeit more expensive) competition of late, may cause the camera to have some problems going up against the higher resolution models, if only in terms of the megapixel horsepower race. On the marketing side the competition is fierce; when first announced in early 2002 the SD9 was rumored to be priced at about $3000; now, upon release, it's going for about $1800.

But as Sigma and Foveon rightly point out, it ain't just a matter of megapixels, but what the chip itself delivers. In terms of image quality right off the card the Sigma SD9 is terrific. But for those who insist on getting max file sizes (and who have many memory cards of large capacity), the SD9's 10MB output might just seem too little too late. For everyone else who loves vivid color and incredible dynamic range, it comes in just about right.

For more information, visit Sigma's web site at

Camera: Interchangeable lens SLR, Sigma mount lenses
Memory Card: CompactFlash Type I and Type II
Lens Coverage Factor: 1.7x (e.g., a 50mm lens on a 35mm camera equals 85mm equivalent)
Sensor: Foveon X3, 3.43 megapixels, 12-bit RAW format
Interface: USB 1.1, Video Out, FireWire
Autofocus: Passive, with Single and Continuous mode
Metering: Eight-segment Evaluative, CWA, Center (Partial Spot)
Exposure Modes: Program AE, aperture- and shutter-priority, manual
ISO: default at ISO 100; 200 and 400
Exposure Overrides: +/- 3 EV, AE Lock, Auto-bracketing
Shutter Speeds: At ISO 100, 1/6000 to 15 sec; at other ISOs, 1/6000 sec
to 1 sec. Flash sync at 1/180 sec.
Power: Lithium CR 123A (2), plus (4) AA type or (2) CR-V3
Size: 6x4.72x3.1"
Weight: 28.4 oz
Price: Street, $1799. Sold without batteries or memory card.

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