Ricoh looks to increase dynamic range with CX1
Feb 20, 2009 at 16:00 GMT
Following the release of its CX1, CMOS-based, zoom-compact, we asked Ricoh about some of the technologies included in the camera. As well as using a CMOS sensor that allows rapid continuous shooting (a rate of four frames per second at full resolution puts the CX1 well into entry-level DSLR territory), Ricoh has built-in a couple of features that aren't commonplace. Takashi Hongoh, General Manager of the company's Research and Development department, explains some of them.
The CX1 has a couple of interesting points on its specification sheet, including a high resolution LCD and a focus bracketing mode for macro work but the thing that caught our attention were the two features added to boost dynamic range. We asked Ricoh why these had been added and who they were aimed at.
'The dynamic range of digital cameras is narrower than that of film,' says Hongoh: 'the challenge was to overcome this weakness of digital. The CX1 has two features to help address this issue. We believe users who are interested in image quality are the people who will most appreciate these features.'
Most digital camera users will be familiar with the loss of detail or color accuracy in bright parts of an image. In general terms, most digital cameras' green photosites tend to be the most sensitive. This is, in part, because the green dyes of the color filter array tend to allow a wider range of light frequencies through than the red or blue dyes but also because of silicon's inherent sensitivity to the red/green end of the visible spectrum. As a result, green photosites are often the first to 'clip' in bright situations, leading to washed-out regions with incomplete color information.
To prevent this, Ricoh has developed an algorithm that re-creates lost green values from the neighboring red and blue photosites, when this happens. 'This is not a normal part of demosaicing,' says Hongoh: 'this is something we have developed ourselves - and there is a dedicated circuit in the CX1 that conducts this processing.'
'This feature will appeal to customers who are very particular about image quality. It helps to suppress white-out and expands dynamic range by up to 1EV compared to previous models. And it's always active,' says Hongoh. This is in contrast to many existing dynamic range expansion technologies that limit the available ISO range (and can result in increased noise), or reduce the camera's performance when engaged.
For more extreme lighting situations, there is also a built-in high-dynamic range mode. This shoots two, differently exposed, images consecutively and combines them to enable to capture of a greater dynamic range than would be possible in a single exposure. The company claims the CX1 will be able to capture and convey dynamic range of up to 12EV. However, Hongoh stresses that its feature isn't trying to produce the fashionable, heavily-processed 'HDR-look.' 'it aims to portray the scene in as natural a way as possible,' he says.
We look forward to receiving a CX1 to see how these technologies work in the real world and in our tests.