Digital Camera Buying Guide - Basics

6 Megapixels	3 Megapixels	1 Megapixel

All digital pictures are composed of tiny dots, called pixels, which are arranged in a grid. A megapixel corresponds to roughly one million pixelsFor example, a 3 megapixel image is composed of about 3 million dots. Megapixels are used to describe the precision of a digital camera. The more megapixels, the more details a camera can capture.

Original	Optical zoom 4X

Optical zoomIs always a property of a camera`s lens. A camera without a lens, cannot have optical zoom. is the ability of a camera to photograph a smaller area from a given point of view. The effect is very similar to getting closer except that perspective changes, meaning that the relative distance between objects does not always stay the same. Optical zoom is measured by how much closer the camera can get compared to its widest setting. For example, a 2X optical zoom can make a subject appear twice as close.

Digital zoom refers to a digital camera's attempt to emulate optical zoom. Digital zoom gives the impression of getting closer to a subject without actually capturing any more detail. Digital zoom is the equivalent of cutting the center of a picture and blowing-up just that portion. Digital zoom must be ignored when purchasing a digital camera because it can easily be done better by computer after a picture is taken.

LCD stands for liquid crystal display. It refers to the small screen on the back of a digital cameraVery old cameras may not have an LCD. which is used for viewing the pictures you took and, in most cases, to preview the picture you are about to take. When an LCD previews the image correctly, it is called exposure-priority as opposed to display-priority, which shows a bright and clear image regardless of exposure.

LCDs are described by their sizeA 2" LCD measures 2 inches diagonally. and by their resolutionA 115K pixel LCD has 115,000 pixels. High-end cameras, called DSLRs, are normally used through an optical-viewfinder (OVF) but recent models can sometimes preview images as well, although either with slow autofocus or incomplete frame-coverage.

This is the part of the camera that can be used to look at a subject. While an LCD can be used as a viewfinder in most cameras, the majority of digital cameras also have either an optical viewfinder or an electronic viewfinder, called EVF. When the photographer sees through the camera it is called an optical viewfinder. Optical viewfinders show less than what will be pictured. An EVF is a miniature LCD showing the same thing as the camera's main LCD. An EVF shows exactly what will be pictured but not as precisely as the human eye.

A very common feature of modern digital cameras is the ability to produce short video clips. These clips are made by rapidly taking a sequence of low-resolution images.

Movie mode is described by its resolutionThe number of pixels taken in each image, frame-rateThe number of frames taken each second, durationThe length of the longest video clip that can be captured when enough memory is available and its ability to record sound or not. No DSLR has a movie mode.

High Definition (HD) Video: 1280x720 resolution or more.	HD video has a resolution of at least 1280x720 and as high as 1920x1080.
High-Quality Video: over 320x240 resolution but less than HD.	High resolution video has more than 320x240 pixels. Most commonly it has VGA resolution or 640x480.
Low-Quality Video: 320x240 resolution or less.	Low resolution video is 320x240 (Quarter VGA) or less.