What's Better 3CCD's or 1 MegaPixel CCD

by Andrew Alexander

Published on Dec 14, 2001 12:00 AM
Add to My Yahoo!




For each of the 12 days leading up to Christmas were answering one commonly asked question. So, before your true love gives you four calling birds, let’s look at today’s frequently asked question. When you look at a camcorder’s vital statistics on paper, you might see something like this:

Sony DCR-TRV30
* MiniDV Recording
* Megapixel CCD DV Handycam® Camcorder (1/4"﷓1,550K Pixels)

Canon XL-1
* MiniDV Recording
* 3CCD 1/3" Pixel Shift (charge coupled device) 270,000 pixels (250,000 effective pixels)

1,550,000 pixels versus 250,000 pixels? Isn’t it better to have more pixels rather than less? Isn’t bigger better? And why the heck would I pay $4,000 for an XL-1 when I can pay $1,700 for a TRV30?

What the heck is a CCD, anyway?

To recap, a CCD is a "charge coupled device" - the part of the camera that accepts light from the outside world and translates it into the ones and zeros that form a digital picture or video. The more pixels you can get on a larger space, the better, but only until a point.

This is a classic case where the numbers don’t tell the whole story. First let’s break down the Sony numbers for a moment. Yes, the CCD has 1,550,000 pixels, but it’s important to note that this number is relevant for taking still pictures only. When shooting video, it will only use around 300,000 pixels. This is simply because the imaging component of the camera (the part between the CCD and the tape) can only process so much information at a time.

Now, let’s look at what it means for a camera to have more than one CCD.

It may interest most of you to know that while the image you see on your LCD screen is in colour, that’s not original how your camera saw it. In fact, when it came into the camera through the CCD, it was in black and white. A specialized filter is used to translate the particular shades of grey into red, green and blue, and the combinations of these colours make up the entire colour spectrum. With one CCD, there’s only so much detail the camera can take in and some concessions have to be made so that one colour doesn’t wash out another.

With a 3-CCD camera however, there is actually one CCD devoted to each of the red, green and blue colour spectrums. A special prism is set up to convert the light entering the camera into the three different colours, they are processed separately, and then combined into a final image. The result is superb detail and accurate colour representation. So what you’re paying for is basically, three different cameras put into one.