The first step is to determine how you will use the camera most of the time. Ask yourself these two questions:

How much flexibility to enlarge images do you need? If you mainly want to make 4x6 snapshots, a camera with 4- or 5- megapixel resolution should be fine. It will also make an 8 x 10 print of an entire image without alteration that won't look much different than one from a 6- or 8- megapixel model.

But to enlarge the image more or enlarge only part of it, you'll want a camera with resolution of 6 megapixels or greater.

How much control do you want over exposure and composition? Cameras meant for automatic point-and-shoot photos, with a 3x zoom lens, will serve casual shooters as well as dedicated hobbyists much of the time.

The full-featured cameras in the advanced compact and super-zoom categories offer capabilities that more-dedicated photographers will want to have.

Two of the more important capabilities are a zoom range of 5x to 10x or more, which lets you bring distant outdoor subjects close and also lets you shoot candid portraits without getting right in your subject's face, and a full complement of manual controls that let you determine the shutter speed and lens opening.

Once you've established the performance priorities that you need from a camera, you can narrow your choices further by considering these convenience factors:

Size and weight.

The smallest, lightest models aren't necessarily inexpensive 4- megapixel cameras.

And the biggest and heaviest aren't necessarily found at the high end. If possible, try cameras at the store before you buy. That way, you'll know which one fits your hand best and which can be securely gripped.

Battery type and life.

All digital cameras run on rechargeable batteries, either an expensive battery pack or a set of AAs.

The best-performing cameras offer at least 250 shots on a charge, while the worst manage under 100.

I think it's more convenient to own a camera that accepts AA batteries. You can buy economical, rechargeable cells (plus a charger) and drop in a set of disposable lithium or alkaline batteries if the rechargeables run down in the middle of shooting.

Camera Speed.

With point-and-shoot cameras, you must wait after each shot as the camera processes the image. Most models let you shoot an image every few seconds, but a few make you wait 5 seconds or more. They may frustrate you when you're taking photos of a subject that is very active, such as a child.

Your other cameras

If you own a film camera with interchangeable lenses, you can probably use those lenses on digital SLRs of the same brand.