When digital cameras first came out, they were very expensive, hard to use, and the results were, in layman's terms, terrible. They began to come down in price, and the quality of their images has continued to improve--to the point that they are used by insurance adjusters and real estate agents with acceptable results.

It's a useful tool. A digital camera can serve as a site inspection tool. Images can be downloaded to your laptop each evening, and even sent as an attachment by e-mail back to the home office. Some of the current models also allow you to capture short segments of video or audio (to narrate information about the image). Since they're more compact than 8mm camcorders, and don't use magnetic tape, digital cameras should survive the rigors of site inspections in a little better condition than a video camera. If you are capturing images for Web use, or for electronic presentations, then a digital image is ideal.

And they're affordable. The very best digital cameras still cost upwards of $30,000, but there are a number in the $250 to $900 range that function well. And with the cost of color printers and scanners in the $300 range, digital photography is now within reach.

But choose the right one. Here are the key variables:

* Image quality--Resolution is a crucial specification. The number of pixels a camera creates determines the size of the file that can be output with acceptable results. The standard minimum resolution of the current cameras is 640x480 pixels--more than you need if you are doing just Web pictures. The maximum resolution ranges from 1,152x864 pixels to 1,600x1,200 pixels. This resolution allows you to print five-inch by seven-inch prints on photo quality paper similar to the paper used to print to 35mm photos. But you often have to lighten or darken the image with software that comes with the camera. Each image takes several minutes to print and can cost up to 75 cents for paper and ink.

* The term megapixel means that the total number of pixels that a two-dimensional area can capture is one million or more. The term is mostly marketing hype.

* Memory--When you take pictures without film, you need to store the images somewhere. Most digital cameras, in addition to their standard storage, have some sort of removable storage medium. This is important as you can run out of storage quickly. The most common storage methods are CompactFlash and SmartMedia. The CompactFlash cards are somewhat chunkier, but can hold up to 64MB of data. The miniature SmartMedia cards hold a maximum of 16MB. Some camera manufacturers give you the option of saving files onto standard 3.5-inch floppy disks, but they are limited in the amount of data they can hold and are slow compared to the other memory cards. The higher the resolution of the pictures you take, the fewer images can be stored in the camera. Often you can get only five or six images before you are out of standard storage. If you are shooting with minimum resolution, you can get from 38 to 100 images before needing to download.

* Downloading files--Transferring images to your PC is not a quick operation. Many of the cameras use a serial-port cable for the transfer, and it can take from 30 seconds to two minutes or longer to transfer each photo. A few of the newer cameras have a USB port as well as a serial one--this is much faster (and you must have a USB port on your PC).

* LCD displays--Most of the cameras now on the market have color LCD displays. These allow you to compose shots and view the photos stored in memory. But they drain batteries fast, so you still need an optical viewfinder. Depending on how much you are using your flash and the LCD display, your battery might last as little as 30 minutes or as long as two hours (depending on the model). You should carry extra batteries (AA) at all times.

* Zoom capability--Today's cameras usually offer a zoom feature. Optical zooms are preferred because you can zoom precisely without degradation in quality. Digital zooms usually offer a single magnification level, and at the lowest resolution.

* Video output--This allows you to view your images on a standard TV or computer monitor.

Sales of digital cameras continue to skyrocket. There could be room for one in your site inspection briefcase.