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Tuesday, December 15, 2009

The Digital Decisive Moment

We’re entering an era of new possibilities, where low-noise and high-ISO digital capture is defining new aesthetics. And it’s not just about low-light shooting.

This Article Features Photo Zoom

According to Westfall, CMOS improvements from the top down include larger microlenses positioned above each photodiode and closer to the sensor surface to improve light-gathering efficiency; improved Bayer filters with higher transmittance; semiconductor fabrication improvements that enable more powerful photodiodes; higher efficiency in converting light to an electrical signal within the sensor; and improved external noise suppression.

“The net result of the CMOS improvements,” Westfall says, “is a cleaner signal coming out from the sensor unit before the image data is exported to the rest of the image-processing chain. Thus, the CMOS improvements apply to full-sized RAW files, as well as in-camera JPEGs and movie clips.”

Very low-light moments like this one can now be rendered with little or no noise. Also, photographers have the flexibility to shoot scenes like this handheld, which is critical for street photography.
Another example of the importance photographers now place on ISO, even over resolution, is Nikon’s top-of-the-line D3S. Armed with a nominal 12.1-megapixel sensor, its ISO range can extend to a whopping 102,400. According to Nikon Senior Technical Manager Lindsay Silverman, the choice to improve image quality
in lieu of image size was deliberate.

“When the D3S was introduced,” he says, “instead of making it a higher-resolution camera, Nikon engineers decided to keep the resolution and large pixel size but opted to improve the sensor characteristics themselves. The D3S uses a newly developed image sensor, which has been refined from the D3 to further minimize noise generated by the amplified signals. This contributes to exceptional image quality and spectacular saturation, even at high ISO settings such as ISO 12800.”

Silverman explains that the original D3 marked the first time high ISO settings such as 3200 and 6400 provided low noise and rich color. That camera, like the D3S, utilized a full-frame FX-format sensor that provided high resolution and a large pixel size. At 8.45 microns, the larger pixel produces a higher signal-to-noise ratio and better dynamic range—which equates directly to less noise across ISOs.

A New Look For Photojournalism
Improving DSLR sensor size, pixel size and construction has led the way to lower noise at unprecedented ISOs. While its impact is obvious for a variety of subjects, from sports action to wildlife photography, it’s nowhere more revolutionary than in documentary photojournalism. Gerd Ludwig’s “Moscow Never Sleeps” piece for National Geographic was undertaken solely because of advances in ISO sensitivity—from the previous generation of technology. Ludwig insists the story wouldn’t have been possible with film.

Shooting indoors, in low light and outside after dark, Ludwig shot digitally at ISO 1600 with Canon EOS-1Ds Mark II and III cameras and equated the look to 400-speed film. The effect he achieved, the new aesthetic provided by the technology, was a sense of place even in low light. He claims that it’s the single biggest aesthetic achievement that digital capture has provided, because instead of sacrificing ambient light for the illumination of a flash, he can balance the two more seamlessly. And with newer cameras and even higher ISOs, the effect is revolutionary.


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