New sensor designs and formats, as well as improvements in manufacturing, promise higher resolution and less noise, with little tradeoff in terms of cost.
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In an effort to boost resolving power, Fujifilm designed its new X-Pro 1 camera body to have no low-pass filter in front of the sensor. Instead, it modified the color filter array to minimize moiré in images.
Less noise, faster data readout, more resolving power. That’s the buzz on next-generation sensors.
As usual, size matters. The larger the imaging sensor, the greater chance of a defect, driving up their cost to manufacture. But larger sensors can accommodate physically larger pixels that capture more light and typically produce less noise than their smaller counterparts. Those qualities make a huge difference to photographers.
Sensor makers’ need to balance cost and quality has led to lots of experimentation and a burst of innovation. New models include the nearly APS-C-sized sensor in the Canon PowerShot G1 X and Fujifilm’s X-Trans sensor with its unique color filter array in the new X-Pro 1 (illustrated above).
Fujifilm is trying to add resolution by scrapping the low-pass filter most digital cameras have in front of the sensor, where it works as an anti-aliasing filter to fight moiré effects. The X-Trans uses a color filter array that is said to mimic the grain in film, which forms a random pattern. Fujifilm believes this will cut moiré while eliminating a layer of glass for a sharper image.
Fujifilm is not alone in removing the low-pass filter—Nikon’s D800 can be purchased without one. And new software has also begun to account for moiré: Both Adobe Lightroom 4 and Nikon Capture NX 2 will include a tool to reduce it.
Thanks to advances in manufacturing, better-performing sensors have begun to appear in more and more compacts—even point-and-shoots. “It’s remarkable that backside-illuminated (BSI)sensors have found their way to the consumer market,” says Eric Fossum, professor of engineering at Dartmouth’s Thayer School of Engineering and the primary inventor of the CMOS sensors found in most of today’s cameras.
“To make them, you have to sandwich a second wafer on top of a normally processed wafer, then grind the first wafer down to just a few microns thick and make it perfectly smooth. The chance of something going wrong at some step is pretty high. When you mate those two wafers together, if you get a single particle of dust trapped between them, you lose at least one sensor.” The payoff? Larger pixels in the same amount of space—for both higher resolution and less noise. As manufacturing capabilities advance further, we expect to see larger and larger BSI sensors.
Pixel counts will keep rising, too. Tetsuya Yamamoto, operating officer and general manager of development headquarters of Nikon’s imaging company, says, “We still have to improve the technology, so we still think it is helpful to raise the pixel count. We also have to develop for dynamic range, but as we learn how to make pixels smaller, we also learn how to deal with other issues to consistently deliver excellent image quality. There must be a balance between resolution and noise, but we will still see higher pixel counts.”