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May 15, 2002
Choosing a Classroom Digital Camera
By Jeffrey Branzburg
This page is designed specifically with the new-to-technology educator in mind. Please feel free to reproduce it for use in your teacher training sessions or other staff development efforts.
Digital photography can trace its roots back almost 40 years, when NASA needed a technology for spacecraft to send images back to Earth. Digital images are stored in computer memory and are able to be transmitted like any other computer file.
When choosing a digital camera, we are presented with a wide (and sometimes confusing) selection of features to consider. Here is some information to help you make the best choice.
Megapixels
The term "pixel" means "picture element"-the number of "dots" that make up a picture. A picture on the Web needs only 72 pixels per inch; a medium-quality print needs about 150 pixels per inch, while a high-quality print requires at least 300 pixels per inch.
A megapixel is approximately 1,000,000 pixels. A 3-megapixel camera can produce a medium-quality print of up to about 11" x 14" and a professional-quality print up to about 5" x 7". Similarly, a 2-megapixel camera produces a reasonable-quality print of up to about 8" x 10" and a high-quality print of up to about 3" x 5". The newest 5- or 6-megapixel cameras have the ability to print even larger.
Storage Media
The earliest digital cameras stored images on memory within the camera. Today, storage is on a variety of removable devices, from floppy disks to CDs to "media cards."
The most popular storage device is the media card. As small as one-half inch wide, some media cards can store up to 384 megabytes of information-the equivalent of over 270 floppy disks. There are a number of different types of media cards, such as the Smart Media card, the Memory Stick, and the CompactFlash card. Be aware, though, that the different types of cards are not compatible with each other. For example, a camera that uses a SmartMedia card will not be able to use a Memory Stick. Because the media card is removable, the camera effectively has no limit on the number of pictures that can be stored-just remove the card, put in a new one, and continue snapping pictures.
There are a variety of devices available with which you can transfer your pictures from the media card into your computer. You can connect your camera to your computer via a cable or use a floppy disk adapter (put the media card into the adapter and then into the floppy drive to access the pictures), stand-alone card readers, and even a mouse with a slot in which the card can be placed.
The Sony Mavica line of digital cameras stores photos on standard 3.5-inch floppy disks. Take the pictures, remove the floppy disk from the camera, put it into the computer, and access the photos. This is an extremely easy system for students to use-plus, they can take their pictures home on the disk. The disadvantage: only 1.4 megabytes of storage per floppy, and the camera needs to be larger in order to accommodate the size of the floppy disk. However, one of the Mavica cameras even stores directly onto CD, for 156 megabytes of storage.
Batteries
Battery options vary from camera to camera. Standard AA batteries in a digital camera will use up power quickly; nickel metal hydride (NiMH) batteries are rechargeable and provide extended life.
Optical or Digital Zoom
There are two types of zoom lenses available on a digital camera: optical and digital. An optical zoom lens is just like the zoom lens on a traditional film camera. Press a button and the lens zooms in or out to bring the image closer or further. A digital zoom lens emulates this process using software, but can lead to lower image quality as the camera lowers the resolution in order to provide a closer view of the image.
For more information on digital cameras, see "Getting the Perfect Picture" in T&L's January 2002 issue.
Other Considerations
In addition to the features and choices above, you should also be aware of these:
LCD Screen. Most digital cameras have an LCD (liquid crystal display) screen, on which you can see what your picture will look like and review pictures you have taken.
Flash. Like film cameras, many digital cameras come with a built-in flash for taking pictures in low light.
Software. Digital cameras include software with which you can edit your photos to eliminate red-eye, crop, rotate, and lighten or darken your pictures. Since the software is included in the price of the camera, don't expect it to be of professional quality. If your needs are such, then you will want to invest in commercially available packages such as Adobe Photoshop.
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