Lesson 1: Digital Photography Primer

Resolution and Pixels

Instead of using film, digital cameras focus the light onto an electronic sensor that records the image as a series of dots, or pixels. The brightness of each pixel is defined by a numerical value of red, green and blue, (RGB) which are the three colors that make up all digital images whether recorded in a digital camera or viewed on a computer monitor, which also renders images and text as colored pixels. Digital cameras are measured in Megapixels, (Mp) or millions of pixels, which corresponds to the number of pixels that make up the sensor. Essentially, it is this numer that determines the amount of detail that the camera is able to record, and the more pixels that make up an image, the higher the resolution. i.e, a 6Mp image that is about 3000 x 2000 pixels in size contains more detail than a 3Mp image, which is 2048 x 1536 pixels in size.

Most consumer point and shoot cameras these days have sensors in the 5-7 Megapixel range, which is adequate for most people. Images of this size are high enough resolution to print up to 8x10 without any noticible loss of quality, even larger, depending on the clarity of the image. Trying to print an image too large will result in pixelated, or distorted image that appear blocky, jagged and generally unacceptable. Those who wish to create professional quality images that can reproduce at much larger sizes should consider a digital SLR that shoots at 10Mp and higher.

There are always occasions when you don't need the largest image possible, and most cameras give you the option to shoot at smaller resolutions. The trade off for quality and file size is that you can store more images to your memory card, and smaller file size images are fine for many applications, such as emailing or the web or viewing on a TV. Even a 3 Mp will view full screen on all but the largest computer monitors, since monitors render images at 72 dots per inch (dpi) whereas a printed image is rendered at 200-300dpi.