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Fujifilm has today announced the new 'SuperCCD SR' sensor type. This announcement is the second of two which mark SuperCCD's fourth generation. The SuperCCD SR (Super Dynamic Range) offers almost two stops more dynamic range than conventional CCD. Beneath each microlens on the sensor surface (a photosite) are two photodiodes, the primary captures a dark and normal light levels (more sensitive), the secondary captures brighter details (less sensitive). The signals from the two photodiodes are intelligently combined by the camera to deliver an image with extended dynamic range. The first Super CCD SR sensor will have an effective resolution of three megapixels.
We were fortunate enough to be introduced to the new SuperCCD SR technology at a press briefing held by Fujifilm UK last week. Fujifilm introduced the SuperCCD SR as a technology designed to simulate the extended dynamic range of negative film. In their presentation it was explained that negative film is made up of layers of differing sensitivity which deliver a very wide dynamic range. SuperCCD SR was designed to simulate this by having two photodiodes which have different sensitivity.
Note that the slides below are from a Fujifilm presentation given to UK journalists.
|SuperCCD SR structure diagram, one microlens, one color filter, two photodiodes per photosite||SuperCCD SR designed to replicate negative film by having two photodiodes of different sensitivity|
|Primary photodiode has high sensitivity but a relatively narrow dynamic range, captures dark and medium tones||Secondary photodiode has low sensitivity but high dynamic range, four times that of the high sensitivity photodiode|
|Camera's DSP processor combines the output from the two sets of photodiodes to produce the final 'extended dynamic range' image||The time flow of capture, both photodiodes are exposed at the same time, primary is read first, secondary is read last|
|Simulated advantage of SuperCCD SR||Simulated advantage of SuperCCD SR|
Press Release (Fujifilm UK):
Fujifilm unveils Super CCD Type SR technology for new generation of digital cameras
Fuji Photo Film (UK) Ltd today announced a major innovation in digital photography. Already positioned at the vanguard of the photographic industry with its ground-breaking Third Generation (3G) Super CCD, Fujifilm has upped the digital stakes with the launch of Super CCD SR, part of the company's Fourth Generation of Super CCDs.
Until now, discussions surrounding digital imaging technology have concentrated simply on the number of megapixels provided by manufacturers' cameras. Fujifilm is now refocusing these discussions on the issue of the level of detail that can be captured, with the introduction of this new Super CCD. Fujifilm's Super CCD SR will provide a truer representation of the actual subject being photographed, revealing highlight detail and increased dynamic range, and resulting in stunningly detailed images - particularly in dark and highlight areas. Fujifilm has dubbed this advance 'High Fidelity Photography', a reference to the sensor's extraordinarily accurate rendition of detail - very similar in principle to the technology advances that led to the development of audio 'hi-fis'.
Where once a single photodiode* was responsible for capturing the full range of light strengths at a single location on the sensor, Fujifilm has now paired two photodiodes per photosite**: a larger, primary photodiode adjusted for high sensitivity, with the secondary photodiode for lower sensitivity. When combined, they offer four times the dynamic range of conventional photodiodes.
Adrian Clarke, Director of Consumer Products, Fuji Photo Film (UK) Ltd,
said, "We're hoping that people will look back at this day as a turning
point in digital photography - a point when people stop asking merely
how many pixels there are, and start to question what those pixels actually
do." Anyone who photographs in a range of conditions - whether it's
a sunny day, a sky with clouds, while using a flash, or any bright object
- will benefit from the Fujifilm Super CCD SR. The core benefits of the
An explanation of Super CCD SR
Super CCD SR uses a new CCD arrangement, based on the advanced octagonal sensor arrangement that Fujifilm pioneered with 3G Super CCD, but taking the concept even further with a 'double honeycomb' shaped photodiode structure.
Not one, but two photodiodes capture information on the same area of the image. The sensitive primary photodiode registers the main volume of light reflected off the subject (similar to a conventional Super CCD photodiode), whilst the secondary photodiode captures highlight information from the same part of the image. Because it is set at a lower sensitivity than the primary photodiode (in other words, records a darker image), the secondary photodiode is able to 'see' additional detail in bright areas that is beyond the reach of conventional photodiodes.
Schematic of Super CCD Type SR (Double Honeycomb) sensor layout:
This combination of primary and secondary photodiodes produces an image that is more richly detailed than conventional CCDs, resolving more detail in highlight and dark areas of the image.
With three million photodiode pairs in three million photosites on the entire sensor, the camera's LSI algorithms then calculate the intermediary values, giving a file output of six million pixels***. With six million photodiodes and a six million output file, resolution will improve beyond current 3G Super CCD technology, however Fujifilm is keen to stress that it is not a 'true' six million pixel CCD.
According to Adrian Clarke, "With sophisticated imaging technologies,
the real benefits can sometimes be on the obscure side, however this is
not the case with Super CCD SR. The user will immediately see better results
in bright sunshine, better flash results, improved resolution of objects
within bright areas, such as cloud detail within the sky, and finally
an increased exposure tolerance in difficult lighting conditions. Every
photographer will recognise this as good news."
As can occur with the introduction of new technology innovations, it is important to avoid ambiguities with the application of technical terms that have been used for existing technologies. For this reason, Fujifilm has clarified the meaning of the following words:
* Photodiode: A single, light-sensing element on a sensor.
** Photosite: The area on a sensor where the light from one point of the image is received. The light entering the photosite passes through one microlens and one colour filter. With a traditional sensor, there is one photodiode beneath the microlens, whereas with Double Honeycomb Super CCD, there are two photodiodes: a primary and a secondary photodiode.
*** Pixel: A final point of picture information in the outputted image. This normally equates to one printed 'dot', or a square of information on the image when displayed on a monitor.
An explanation of Dynamic Range: Unlike the human eye, which can rapidly adjust to differing intensities of light inherent within a contrasty scene, photographic media (film and digital sensors) are constrained by having to align themselves to expose correctly for a given intensity of light. If the camera exposes bright areas correctly, the shadow areas darken out, and detail is lost. Conversely, if the camera exposes shadow areas correctly, the bright areas will appear as burnt-out whites. A camera with good dynamic range will possess the exposure flexibility to accommodate these extremes and expose both bright and shadow areas correctly.