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Sigma SD10

Sigma's digital SLR uses Foveon's latest "X3" sensor technology to boost ISO and reduce image noise.

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Page 12:Test Results & Conclusion

Review First Posted: 10/26/2003

Test Results

In keeping with my standard test policy, the comments given here summarize only my key findings. For a detailed commentary on each of the test images, see the Sigma SD10's "pictures" page.

As with all Imaging Resource product tests, I encourage you to let your own eyes be the judge of how well the camera performed. Explore the images on the pictures page, to see how the SD10's images compare to other cameras you may be considering.

  • Color: The SD10 generally produced very good color in my testing, with notable improvements over the performance of the earlier SD9 in this regard. Colors were hue-accurate and appropriately saturated, across the spectrum. Skin tones could be good to excellent, but the results there depended strongly on the appropriate choice of white balance setting for the lighting. White balance was fairly good, but there were often slight color casts left in images that would need to be corrected-out in the Photo Pro software. Overall, I'd rate the SD10's color as good to excellent, marred only by the tendency of the white balance system to leave color casts in the final images.

  • Exposure: The metering system in our evaluation unit of the SD10 had a tendency to slightly underexpose some subjects by about a third of an f-stop, but this is one of the few areas in which we've heard that the firmware will be upgraded in final production units. On a positive note though, the SD10's powerful histogram display and over/underexposure warning option makes it easy to see when the exposure is off a bit and to correct for it. One pleasant surprise with the SD10's images was the amount of dynamic range I saw in them: The camera generally did a good job of holding onto highlight detail without plugging the shadows excessively. While I didn't have an SD9 to compare it to side by side, this seems to be another area of significant improvement, as I remember the SD9 having a tendency to completely lose highlight detail at the slightest provocation. (And the SD10 seems to do much better in not producing odd saturation errors as highly saturated colors become overexposed. The odd desaturation that the SD9 exhibited under these circumstances is still present occasionally, but not nearly to the degree seen in the SD9. Some of the biggest exposure-related news with the SD10 actually has more to do with the software than hardware, namely the "Fill Light" function in the Photo Pro application. See the Pictures Page section on the closeup outdoor portrait shot for an example of this, but it really was remarkably effective in mimicking the effect of a fill light or reflector in very contrasty shots.

  • Resolution/Sharpness: As before, the 3.4-megapixel 3-color-per-pixel Foveon sensor in the SD10 produces overall resolution approaching that of a 6-megapixel sensor using a conventional color filter array pattern, with "strong detail" present in the laboratory resolution test image out to about 1,050 lines vertically, and 1,200 lines horizontally.

    UPDATE: The softness I thought I saw in the SD10's images appears to simply be the result of differences between the 50mm lenses I used to test this unit and the original SD9. I shot both cameras' resolution target shots with Sigma's 50mm f/2.8 macro lens, supposedly one of the sharper lenses Sigma makes. The one difference was that the SD9's shot was snapped at f/4.0, while the one for the SD10 was taken at f/8.0. If anything, I'd have expected the SD10's image to be a little sharper, but the opposite was the case. I commented on this in the first version of this review, and on the fact that I thought a number of my test images from the SD10 looked a little soft. Foveon contacted me to ask about this, as their own internal tests had shown essentially identical performance between the two sensor versions. Determined to get to the bottom of the issue, I had Foveon ship me an SD9, so I could test with the same lens, at the same aperture, under identical conditions. I set up the ISO-12233 res target and shot it using virtually identical exposure times. (The 1/2 vs 1/3 stop adjustment difference between the two cameras prevented me getting the identical exposure time, but they were very close.) Processing the images from the two cameras identically produced.... Virtually identical results. Thinking that the lens could possibly be sharper at f/4.0 (thereby explaining the different result with the earlier SD9), I shot with both cameras at that aperture, and found that the results were decidedly worse. All I can conclude is that there's a fair bit of variation between different samples of Sigma's lenses of the same focal length/aperture, and that the original lens I had with the SD9 was sharper than the sample I have now. (Either that, or there was something else that was optically different about the original SD9, but Foveon and Sigma say there were no changes between that original model I tested and the current one.) I'm badly backlogged on review work at the moment, but will try to find time for some more resolution/sharpness comparison tests between the two cameras.

  • Night Shots: This was an area of huge improvement in the SD10 over the SD9. The SD9 really wasn't usable for low-light photography due to limited ISO, high image noise, and poor AF performance. Every one of these parameters has been improved in the SD10, so much so that the SD10 is very usable for shooting typical night scenes. I'd have to characterize its performance as something below "pro" level though, since the d-SLR competition still smokes it when it comes to image noise with long exposures. The SD10 shows really excellent noise characteristics under bright lighting, in fact producing less noise than much of the competition under those conditions. Noise levels increase disproportionately in long exposures though, resulting in fairly noisy images at light levels you'd encounter when shooting outside after dark. Make no mistake, the camera is quite usable for after-dark photography, but you'll have to accept higher noise levels than you'd find with cameras such as the Nikon D100 or Canon's EOS-10D and Digital Rebel. (EOS-300D outside the US.) Still, for people who've liked the Sigma / Foveon approach, but who have yearned for the ability to shoot under low-light conditions, the SD10 is very good news indeed.

  • Viewfinder Accuracy: The SD10 is a digital SLR, meaning that the optical viewfinder shows the actual view through the lens. (The LCD monitor is for image review and menu navigation only.) The SD10's viewfinder is very accurate, showing approximately 97 percent of the final frame area, better than average, even among SLRs.

  • Optical Distortion: Given that the SD10 is an interchangeable-lens camera, the optical distortion you experience with it will be entirely a function of the lens you're using. That said, the 50 mm f/2.8 macro lens that I used to shoot all my studio shots with was an exceptionally sharp, distortion-free lens.

  • Shutter lag and cycle time: I measured the SD10's cycle time using three different memory cards: A Lexar 24x 256MB, a Lexar 24x 256MB "WA" (Write-Accelerated) card, and a SimpleTech 512MB. While the SD10 supposedly supports Lexar's Write Acceleration technology, there was little difference in buffer-clearing time in my tests between WA and non-WA cards. With a 0.15-0.23 second shutter delay using Sigma's 20-40mm f/2.8 zoom and a prefocus lag of 0.111 seconds, the SD10's shutter lag times were much faster than typical consumer cameras, and on a par with most other d-SLRs I've tested. (The prefocus lag is a bit slower than most pro SLRS though.). Shot to shot speeds were quite good, but the buffer took a long time to clear. Also, as noted above, in non-continuous mode, the interval between the first two shots is quite a bit longer than between subsequent ones, so you may want to use continuous mode for fast-breaking action, even if you don't plan on shooting more than a few frames.

  • Battery Life: Because the SD10 does away with the (onerous) requirement for the extra pair of CR-123 cells used by the SD9, all of the camera's circuitry now operates directly from the four AA cells. As a result AA-cell battery life is a bit shorter than on the SD9 (at around 3.5 hours in capture mode with true 1600 mAh-capacity NiMH cells), but still quite acceptable. - With the highest-capacity NiMH cells currently on the market, battery life will be quite good, indeed. (See the Battery Shootout page for actual performance data on various NiMH cells currently on the market.)


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Foveon and Sigma have made remarkable strides over the last year, as evidenced by the dramatic improvements in the performance of the new SD10 camera over the earlier SD9 model. Many of the limitations of the SD9 have been addressed, and the improvements in image noise levels and high-ISO capability are impressive. Color rendering has also seen substantial improvement, to the point that I'd now rate the SD10's color as "very good to excellent," something I'd not have said about the SD9. While Sigma and Foveon are trying to position the SD10 and its sensor as 10.2 megapixel units, my own tests to date suggest that the camera delivers resolution more equivalent to that of its six-megapixel competition. (I have in mind some additional tests to explore the resolution issue further, but I don't know if I'll be able to get to them, given the current review overload.)

A lot of the success of the SD10 will depend on the price point at which it ends up being sold, and on how the established band of SD9 enthusiasts react to the "look" of its pictures. My earlier conclusion that there were sharpness differences between the SD9 and SD10 appear to have been the result of random variations in performance between the 50mm lenses I originally used to test the two models, despite their being the same model. Repeating the test, using the same lens on both the SD10 and a SD9 seems to show that the two cameras are virtually identical in their sharpness characteristics. So bottom line, the new SD10 should appeal to the same folks who liked the "look" of the original SD9's images, as well as a much broader segment of the market now that image noise has been improved and high-ISO shooting is possible. As with the SD9, the SD10 also has in its favor the relatively low cost and high optical quality of the Sigma lenses, making it quite affordable to build up a considerable "kit" of lenses. I suspect a lot of its success will depend on the price point it hits the market at. (As I'm writing this, in the wee hours of the morning, two days after its announcement, the introductory price still hasn't been set yet for the US market.) If it's priced competitively, it might steal some business away from Nikon and Canon at the low ends of their lines. If it's priced higher though, I'm afraid it will have a difficult time getting traction with consumers.

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