The Super CCD
SR from Fujifilm is
designed to solve the bucket
problem with a technology called
spatially varying pixel exposures.
In simpler terms, the technology provides two
sizes of pails to catch the photon rain. Each of
the light receptor sites in the imaging sensor,
arranged in a double honeycomb pattern,
uses a large and a small photodiode to catch
the same light coming through a single filter.
The large photodiode does most of the
light-gathering work, much like an ordinary
photodiode. It captures detail in shadows, but
overexposes highlights.4
The smaller photodiode is set at a lower sensitivity and
works as if it wears sunglasses. This prevents it from filling
up quickly and causing blooming. As a result, it can capture
the detail information in the areas that are so bright that
they blind the large photodiode, which stares at the same
light with a wide open eye.5
A fast algorithm built in to the camera’s processors com-
bines the readings taken by each pair of photodiodes to
create the optimum exposure for the pixel that they repre-
sent, with each diode providing a proper exposure where
the other can’t. By combining the results, the Super CCD SR
produces a picture comparable to those produced with a
12-bit color scheme, which has a range of 4,096 brightness
levels, even though the photodiodes, individually, yield only
8 bits, or 256 brightness levels.6
CHAPTER 7 HOW LIGHT BECOMES DATA^105