About Digital Photography

How does a film camera differ from a digital camera?
A film camera and a digital camera are very similar in many ways. The biggest difference is how each captures and stores information.

Film Camera
With the conventional film camera you push the button. The shutter is tripped and light reflected from your subject passes through the lens and exposes the film to the image of your subject. You then wind the film to the next unexposed area and get ready for the next picture opportunity.

Developing film into negatives, which are then used to make pictures, is a chemical process. Unless you have the expertise and equipment to develop film, you will need to take your exposed film to a professional to have your film processed.


Digital Camera
The digital camera does not use film. Instead of film, a digital camera has light sensitive computer chips. Like the conventional camera, you trigger the shutter, light comes in and passes through the lens. Instead of exposing film, the light is captured by an array of light sensitive computer chips. When the light hits these computer chips, they emit an electrical charge. The camera processor converts these electrical charges into a digital format (pixels) and stores them in the camera's memory.

Think of a digital camera as just another computer harddrive. It stores your pictures as image files. You can download these files to a computer; edit and print them much like you do other types of computer files.


What are pixels?
Pixels are the building blocks of digital images. Every digital picture is made up of thousands of pixels. The number of pixels in each image affects the quality of the picture resolution. For example, a low-end camera might have 307,200 pixels in one picture. A high-end picture might have more than 5,000,000 pixels in a picture.


What is Resolution?
Simply put, resolution is how you define the sharpness of your digital image. Resolution is often defined as how many pixels per inch (ppi) your image has in both its height and width.

A digital camera that has a 640 x 480 resolution will have 640 pixels in width and 480 pixels in height.
This is a fairly low resolution that works well with email and Web postings. Pictures will print best if they are not bigger than 3” x 5” high.


crisp 3" x 5" photo prints

A digital camera that has a 1600 x 1200 resolution (2 megapixels) will have 1600 pixels in width and 1200 in height.

This resolution gives a crisp 5” x 7” print picture.


crisp 5" x 7" photo prints

A digital camera that has a 2048 x 1536 resolution (3 megapixels) will have 2048 pixels in width and 1536 in height.

This resolution gives a crisp 8” x 10” print picture.


crisp 8" x 10" photo prints

Resolution examples:
Low End Midrange High End
pixels at 640 X 480 or higher pixels at 1600 X 1200 pixels at 2048 X 1536 or higher

 
Digital Photography
About Digital Photography
Photography in the Classroom
Camera Settings
ABCs of Selecting a Digital Camera
The World of Rechargeable Batteries
Choosing Printer & Paper
Photo Tips
Glossary