by Angela Tague
When you start getting serious about digital cameras, there is a lot of technical jargon to decipher. With terms like megapixel, compression, ISO and ASA, you may be looking for some help understanding how it all relates to your digital camera. Once you understand these terms and what they mean for your camera settings, you'll better understand how to use a digital camera to produce high-quality images. Here are some frequently asked questions about digital camera terminology.
What is a megapixel?
Digital camera manufacturers often advertize the number of megapixels they use to capture an image. A megapixel is a 1000-pixel x 1000-pixel square. So, that means that a 1-megapixel image contains 1 million pixels. Think of a pixel as one drop of paint. Your digital camera gathers light through a sensor and digitally encodes colors from the light as individual pixels. The more pixels your digital camera uses to record an image, the more detail you will see in the final image. Digital SLR cameras tend to have bigger sensors, while compact digital cameras have smaller ones.
What is compression?
When your digital camera records an image, it stores it on a memory card. Image files contain a lot of information, and one way to save storage space is to compress the data. Usually, compression involves discarding pixels. Photos stored with low compression require more storage space but are of a higher quality because they retain much of the original photo data. Many digital cameras allow you to adjust data compression settings.
What is the ISO setting?
ISO refers to the film speed on a conventional camera. The more sensitive the film, the faster the shutter speed could be without compromising the picture quality. On a digital camera, you can manually set the speed at which you want to record your images. The lower the number, the more light needed for a proper image. An ISO setting of 100 is ideal for outdoor, sunny images. You might choose 400 for indoor photos with conventional lighting. Sports photos, low-light situations and fast action should be recorded with ISO settings of 800 or faster.
What is the difference between optical and digital zoom?
Compact point-and-shoot cameras often offer two types of zoom: optical and digital. With optical zoom, the camera lens adjusts to zoom in or out. Digital zoom digitally crops pixels around the outer edge of the image, and then blows up the remaining image. Optical zoom will give the best picture quality because the entire sensor and full resolution of the digital camera is used. Digitally zoomed images often look more grainy and soft-focused than optically zoomed images.