The SD10 has no built-in flash, but the camera's hotshoe will accept powerful external flashes, including two Sigma TTL-dedicated strobes. Flash-sync speed is a decent 1/180 second.Like the SD9 before it, the Sigma SD10 offers adequate performance but still lags a step or two behind the competition. Shutter delay varies from about 0.3 second to 1.5 seconds with autofocus, and it's about 0.2 second with manual focus. Shot-to-shot time is slightly more than a second. In continuous-shooting mode, the camera fires at 2.2 frames per second for a six-shot burst, after which a 7-second buffer stall sets in. These figures range from mediocre to poor for a dSLR.
The SD10's autofocus system is a throwback to the early 1990s. It hunts around too much in both good light and bad, and it can't track moving subjects that other midlevel dSLRs handle easily. This, combined with the unimpressive numbers mentioned above, makes the SD10 a bad choice for sports and action shooters.
The camera's "sports finder" viewfinder shows roughly a 25 percent wider field of view than your image will actually record. The area that won't be captured is clearly distinguished by a semitransparent gray mask. We liked the ability to see what's just outside the frame area, but the actual image area is fairly small in the viewfinder, which makes manual focusing more difficult. The camera's LCD is sharp and reasonably easy to use for reviewing images, even in bright light.
Unlike the SD9, all of the SD10's digital and mechanical operations are powered by one battery system--either two CR-V3 lithium batteries or four AA cells.Clearly, the Sigma SD10 is made or broken by the photos its Foveon X3 sensor produces. The X3 is unique because each of its pixel locations contains three vertically stacked photodetectors: one to record red light, one for green, and one for blue. In contrast, all previous single-shot color image sensors use one photodetector at each pixel location with a checkerboard pattern of alternating red, green, and blue filters overlaid on the pixel array. Such chips thus capture only one primary color per pixel and construct full-color images by interpolating the two missing color values for each pixel from the data gathered by adjacent pixels. For more information on the X3, see Foveon's Web site. Foveon claims that compared to conventional imaging chips, X3 sensors will provide much sharper pictures with better color detail and fewer color artifacts such as moiré.
Our tests, both with the SD9 and with this model, bear out some of Foveon's claims. With well-lit subjects that contain very fine detail--finely woven fabrics and highly detailed landscape or architecture shots, for example--the SD10 often shines, making sharper pictures than any we've seen from conventional sensors with twice the pixel resolution. And the X3 sensor is indeed resistant to color artifacting, especially the kinds of moiré that can plague shots of clothing and hair. On the other hand, we did note frequent artifacts--usually thick, blue fringes--around overexposed highlights. Colors in our SD10 test shots were accurate and vivid at the Photo Pro software's default settings.
But what about noise? This was the bugaboo of the SD9, which was worse than the competition at ISO 100 and rendered shots largely unusable at higher sensitivities. The new microlenses on the SD10's sensor make a modest dent in this problem. Our test shots at ISO 100 are very clean--no room for complaint--and they still look pretty good at ISO 200. Significant noise is visible in the shadows by ISO 400--an especially irksome, blotchy, green/magenta discoloration--but some folks might not object to it at smaller print sizes. By ISO 800 and 1,600, our shots were essentially ruined by green/magenta yuck. The noise from settings of ISO 400 and higher also causes a progressive loss of detail. Bottom line: The highest usable sensitivity of the SD10 is about 1EV or 2EV greater than with the SD9 but still far lower than most of the competition.