Bits & P.C.s: New Year’s resolutions—Part Two

Bits & P.C.s: New Year’s resolutions—Part Two

By Richard Heller

In the column last week, I answered part of a reader’s question regarding the settings that should be used to scan images. This week, lets try to address another one of the questions that the reader asked concerning camera resolution and transferring the photos to a PC.

When you take a picture with a film camera, a lens focuses the image onto a chemically treated piece of film. The chemicals completely coat the surface of the film so the dots-per-inch (DPI) is infinite; the quality of the photo depends on the quality of the optics.

When you use a digital camera, the image is focused onto a light-sensitive electronic device usually called a CCD. The CCD is composed of a number of transistors that are sensitive to the three primary colors—red, green and blue. There are three transistors, each detecting a different color, that are grouped together to form a pixel. The amount of light striking each pixel determines the brightness of the image while, at the same time, determining the color.

Because the CCD is composed of a finite number of pixels, and each pixel is separate from the others in the CCD, the smaller the pixels and the greater the number determines the quality of the image that is captured. Because of the spacing between the pixels, the quality of a digital image will never be as great as a film camera.

When you purchase a digital camera, the resolution is given as the number of million pixels that make up the CCD. A 1-mega pixel camera has one million pixels, while a 4-mega-pixel one has 4 million pixels. As long as the size of the CCD is the same, the larger the number of pixels along with the quality of the lens system will create a better image.

The problem you run into with a higher-resolution camera is that the image captured requires more memory in the camera while occupying more space on the hard drive. It is not unusual for a high-resolution camera to contain a 128 or 256 MB of memory card to store the same number of photos as a roll of film. Some of the cameras are even using a CD writer or DVD writer to store the images.

Once the photo is taken, it is necessary to get it transferred to the computer. Originally, the transfer was done through the serial port, but this became unbearably slow as the file sizes increased. Today, the files are transferred over the USB port or the 1394 (Firewire) port. The easiest way to transfer the files is by using a memory card reader that connects to the PC through the USB port. By popping the memory card out of the camera and placing it in the reader, the files can be transferred in a few seconds.

Next week, we’ll look at saving the pictures to a CD to do a slide show that you can play on a DVD player.

Richard Heller is an independent computer specialist who specializes in repairs, installation, upgrades, technical support, Internet sharing, data recovery and diagnostics. If you have any computer or service-related questions, please send them to The Rock River Times or e-mail

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