Camcorder News

Today's announcement of the Sony DCR-PC1000 marks the first camcorder ever to use a CMOS imaging sensor. Previously, all camcorders used CCD technology - however, the digital imaging industry is moving towards CMOS chips which are easier and less expensive to produce.

CCD chips have been used widely in camcorders since the 1970s. The CCD serves in a camcorder to convert the image (light) coming in from the lens into an electronic signal, which can be processed by the camcorder's digital signal processor into digital information which can then be record to tape, DVD or flash media. CMOS chips serve the same function in camcorders as CCD chips.

Both chips are packed with a matrix of pixels. Each pixel is sensitive to light, the more light that the pixel is exposed to the greater the amount of energy the pixel "stores up" during it's exposure to an image. This energy that is stored in the pixel needs to be converted to voltage, so that it can be read by the camcorder. The key difference between a CCD chip and a CMOS chip, is that the CCD chip sends all of the "stored up" pixel energy to a processor outside of the chip where it is converted to voltage, while each pixel on a CMOS chip is able to do this process on it's own. Another way of putting it is that a CCD puts out a signal as electricity, whereas a CMOS chip puts out a signal as computer bits and bytes. The other major difference between CMOS and CCD chips is that many more other camera processing functions can be done on the CMOS chip, whereas with CCD chips those processes must be done through external chips.

The biggest barrier to using CMOS chips in dedicated imaging devices such as cameras and camcorders have been quality issues. CCDs offer lower noise amounts while CMOS chips offer a better dynamic range (darker blacks and brighter whites). The result is that CMOS sensors have typically had extreme problems in low light when compared to CCD camcorders, and because of the importance and difficulty of low light performance for video applications it has been a major barrier for CMOS camcorders. The other problem with CMOS chips is consistency. Early CMOS chips had problems with the consistency of their response, with some pixels performing better than others which creates a large problem with different pixels performing differently in one image.

Possibly the biggest advantage of CMOS chips is that they can be timed and clocked variablly. This allows CMOS chips to perform at any frame rate and also work either as a progressive scan chip or an interlaced chip. The current range in high end prosumer camcorders is 24 frames progressive scan mode, which mimicks the frame rate of film. The 24 frames progressive rate is much different than the 60 frames per second interlaced rate of standard NTSC television. CMOS chips are able to switch between 24 frames progressive, 60 frames interlaced, and any frame rate for that matter much more easily than CCD chips can. Another advantage of CMOS chips is that they eliminate the vertical white line smear problem sometimes found with CCD chips.

Up to now, CMOS chips have primarily been used in low end digital imaging devices such as camera phones, web cams and low cost digital cameras. Because the chips require less power, are smaller and can be produced in volumes at low costs they have worked well for high volume low quality applications in the past. These cameras however are plagued with horrific noise and picture quality problems and are often mocked by digital imaging industry professionals.

Sony got around the major noise problem with CMOS chips by developing a brand new digital signal processor titled the Enhanced Imaging Processor. Without the processor it would be impossible for Sony to produce video with CMOS chips that was comparable to CCD quality video. This processing chip edge may mean that Sony will be able to hold-on to the CMOS camcorder market as the only manufacturer for a while. Of course, the picture quality of the new DCR-PC1000 is yet to be tested.

In late December, Sony Japan announced it would be investing 50 billion yen to build a new CMOS chip production facility according to Asia Times. Already the leader in CMOS chip production, it appears Sony is trying to position itself as a leader in the more competitive CMOS production arena. CMOS chips are considered easier to produce because they can be produced in on a "wafer" in high volumes similar to the methods used on many other computer chips. However, there have been quality issues with CMOS chips - limiting them in the past to camera phones and low end digital cameras.

In September 2004, the Japanese website Nikkei Electronics Online reported that the chip used in the high end digital still camera the Nikon D2X was being produced by Sony. This revealed that Sony has the capability to produce high end CMOS chips for market. High end digital SLR style still cameras from Canon, Nikon and Kodak use CMOS imaging sensors.

While it is clear that CMOS technology is the next step in camcorder imaging, and will one day dominate the processors of all camcorders - it will be a long time coming. While the DCR-PC1000 breaks a new price barrier for Sony in the 3 CCD market, it is not an "affordable" camcorder for most individuals. The DCR-PC1000 itself is no where close to hitting store shelves, and not expected for many months. It seems, for the time being, that most people will have to wait until they will get their own CMOS camcorder.