|Canon DIGIC II Image processor introduction|
Mark Peters : February 17th 2005 - 12:00 CETupdated
Canon DIGIC II Image processor introduction: The Canon EOS 350D Digital features Canon's DIGIC II processor, proven in Canon's pro-series EOS-1Ds Mark II and EOS-1D Mark II cameras. DIGIC II delivers superb image quality, responsive camera performance, faster AF, faster continuous shooting and extended battery life. "There are three critical stages affecting digital image quality," says Brian Worley, Camera Product Manager, Canon Europe. "First the lens determines how the image is transmitted on to the sensor. Then the sensor determines how accurately the light is converted to electrical signals. The third and final stage is the image processor, which dictates how well the signals from the sensor are translated into a viewable image.|
You need to get each step right to make a good image. Get one of them wrong, and you ruin everything."|
With over 60 years of precision lens manufacture behind it, Canon has little to prove in the area of optics. With its own award winning CMOS technology Canon is also well in control of the sensor. With its dedicated DIGIC and now DIGIC II (Digital Image Core) image processors, Canon has revolutionised the way digital images are handled.
Ultra high speed
With the introduction of Canon DIGIC II, Canon brings a solution for doing the high speed calculations necessary in order to providing exceptionally accurate colour reproduction in real time. "DIGIC II operates many times faster than other image processors. It can handle more data in a shorter period to allow more complex calculations to take place," says Worley. "DIGIC II runs not on software as others do but as a piece of hardware built into the camera's circuitry. As such it is able to carry out the duties of a number of separate processing units, effectively replacing them to save both time and space."
Most digital camera manufacturers face a trade-off between camera responsiveness and the amount of processing each image can receive. For high quality images, data received from the recording sensor needs a lot of attention. But working on that data to the extent required in order to optimise image quality takes time, and can hold-up the operation of the camera. To alleviate this problem, many cameras compromise image quality by using simplified processing methods, leaving off or 'dumbing down' certain processing procedures. Large and expensive buffer memories are required to store data during busy periods, to be processed later when the camera is at rest. This creates its own problems when buffer memories become full, causing cameras to freeze until some of the backlog is cleared.
"With DIGIC II, Canon has created a processor so fast it can read, process, compress and write image data back to the buffer between exposures," explains Worley. "This allows continuous shooting with the Canon 350D digital camera without the camera becoming clogged with data. Moreover, each image is subject to the complex and individual processing required in order to deliver superb image quality."
The image quality delivered by DIGIC II is so good that leading photographic agency Getty Images chooses to shoot JPEG rather than RAW images.
Apart from the speed with which it clears data from the camera's buffer, the benefits of DIGIC II are most obvious in the areas of white balance (WB) adjustment.
The camera uses DIGIC II's additional processing power to build an intelligent understanding of the scene to be captured by taking into account factors such as orientation and subject position. This allows more accurate calculation of auto white balance.
"While other manufacturers use systems that divide the scene into hundreds to segments for white balance assessment, the DIGIC II processor in the Canon 350D digital camera has the time and power to look at tens of thousands of segments to build a complex plan of how the scene is constructed. This allows the camera to distinguish between more than one type of light source in a single scene and to treat each area individually," explains Worley.
Another feature of AWB under DIGIC II is what Canon calls 'Feeling Based White Balance'. This is a system that aims to correct casts without destroying the atmosphere of the scene, allowing it to be reproduced in a realistic way. AWB systems that adjust with technical correctness can remove the warmth of a romantic meal for two, the orange/red light of the sun as it dips below the horizon. "This Feeling Based White Balance will reproduce colours closer to the way we see them in different situations, rather than striving to always create a textbook-accurate but sterile image," says Worley.
One of the benefits that has come about with the introduction of DIGIC II is extended battery life. "As the processor is only operating for very short periods, it doesn’t use much power," explains Worley. "DIGIC II is part of the reason that the Canon EOS 350D is capable of taking 600 shots on just a single battery charge."
Investment in R & D
"The development of DIGIC and DIGIC II has been made possible by the vast amount of resources Canon has allocated to research and development over many years, and the company's position as a manufacturer of its own electronic components and circuitry," Worley explains. "By increasing its experience in the manufacture of Application Specific Integrated Circuits (ASIC) for its digital camera production line, Canon has ensured that every major piece of hardware required for the construction of the Canon EOS 350D is provided in-house. This puts Canon in a special position in the digital SLR market, a company that produces every significant element that goes into its cameras, from the lenses to the electronics and internal hardware, and in the case of the Canon EOS 350D, the actual sensor itself."