Digital photography - Buying guide I

Why you want a digital camera? The answer to this question will form the basis of all your other buying decisions. If you want to print digital photographs,then you need a camera with more resolution.If you only want to send snapshots by e-mail or post images on the Internet, you don't need a high resolution camera

Resolution

Digital cameras are rated by the number of megapixels (millions of pixels) they can record. This is also referred to as their 'resolution' and is the single most important factor affecting the price of digital cameras. Quite simply, the more megapixels the higher the price.

Images which are only viewed on a computer screen did not need a high resolution. A computer monitor set to 1280x1024 (which is very large) is only displaying about 1.3 megapixels. Any digital camera rated at about two megapixels is suitable for computer images.

Professional photo shops usually print photographs at 300 dots per inch, and you are likely to be disappointed with pictures printed at less than this standard. A 4 x 6 photograph printed at 300 dots per inch needs an image which has about 2.8 million pixels. That means that digital cameras that are meant to be used for printed pictures should be rated at least three megapixels.

More megapixels doesn't necessarily mean better pictures. All other things being equal (image sensor quality and lens quality) a camera with more megapixels simply allows you to print larger pictures. You also have more options for cropping photos and maintaining standard print sizes.

Budget

You will most likely want to get the best quality images for your money, and that may mean foregoing some of the fancy features such as video and sound recording. Concentrate on lens quality and image sensor quality.

Lenses are available in either plastic or glass. Glass lenses are superior and will produce crisper, cleaner images. The best cameras will be equipped with lenses by well-known manufacturers such as Leica or Zeiss.

Many digital cameras have a zoom function which allows you to get closer to your subject without moving the camera.  There are two types of zoom -- digital and optical. An optical zoom changes the actual length of the lens. Digital zooms simply remove the outside edges of an image and interpolate the result over the area of the image sensor. They do not give as good results as optical zooms and should be avoided if possible.

Image sensors are electronic devices that record the images. The two most popular types are CMOS (Complementary Metal Oxide Semiconductor) and CCD (Charged-Couple Device). CMOS is the cheaper of the two but the image quality is inferior to CCD.

No matter what your budget, a camera with a good quality lens and CCD image sensor will likely give you pleasing digital photographs.