Digital Camera 101

Digital photography may be in, but few people really know how it works. While you don’t need a thorough understanding to choose a good camera, knowing at least the basic concept can help you get the most out of your purchase. Learn more about digital cameras with this guide.

With film cameras, all you needed to know was the difference between a manual, an automatic and a semi-automatic. But the digital boom brought with it a lot of confusion: What’s a megapixel? Why are there now two types of zoom? How do you make digital prints? If buying your first digital camera has you spinning, this guide runs you through the basics to help you make the right choice.

The all-important CCD

In digital cameras, film is replaced by an image sensor or a charge-coupled device. The CCD captures the light that comes in and saves the image in the digital camera’s memory—usually a separate storage card, but sometimes an onboard storage. CCD size is a major consideration when buying digital cameras. Basically, the larger the CCD is, the more sensitive it is to light and the better the image quality. Most compact cameras use a single standard-size CCD, whereas more advanced digital SLRs use larger image sensors.

Megapixels and why they matter

“Pixel” is short for picture element, or the microscopic dots that make up a picture. A megapixel is equal to one million pixels. Megapixels simply refer to the number of dots on a picture, or simply put, how big the original picture is. Consumers are made to believe that more megapixels mean better pictures, although this is not always the case. Megapixels only matter when it comes to print sizes. Two to four megapixels is more than enough for 4x6” prints, while five to six is ideal for larger prints and high-resolution web pictures. Any pixels over 7 million will be pretty useless, unless you’re a professional who likes to make poster-size prints or tarps.

The form factor

Besides the use of the CCD, size is one of the most noticeable differences between film and digital cameras. You can get slim cameras the size of a credit card, or bulky, professional ones that weigh more than your purse. One rule to remember is that style often comes at the price of function. A pocket-size camera offers significantly fewer features than a large one with a zoom lens, although it can still take pretty decent pictures.

Optical and digital zoom

A typical digital camera will have separate values for optical and digital zoom, the latter usually a larger number. Optical zoom works the same in film and digital: it brings your subject closer by moving glass elements inside the lens. Digital zoom only makes the subject appear closer by blowing up the pixels on the center part of the image. In most cases, digital zoom should be largely ignored, as digitally zoomed pictures are seldom of acceptable quality.

Powering up

Power is an important yet often overlooked aspect of buying a digital camera. Digital cameras eat up a lot of power; a cheap alkaline battery will be lucky to last ten shots with flash. A few compact cameras have rechargeable lithium batteries, but most models still use alkaline cells. It’s best to invest in at least one set of rechargeables to save on replacement costs.


On most cameras, the pictures are stored on a removable memory card until they are transferred to your computer. A card usually comes with the camera, although they seldom pack in more than 32MB. Get a larger memory card with your camera, as a 32MB card won’t hold more than 20 pictures on a 5-megapixels model. The card may be removed and plugged into a card reader, but it’s safer to plug in the camera itself using the cable provided with the package. This reduces the risk of damaging the card during transfer.