(Money Magazine) -- The digital camera market is tricky these days. On the one hand, there are models so small they've earned the nickname "credit card" cameras. But an opposite trend has also been showing up at the local electronics store: big honkin' cameras that look more like they should be strapped to Annie Leibovitz at a Vanity Fair shoot than to Dad on vacation.

There are certainly more than just two types of cameras out there in stores--others include budget models that sacrifice size and features for a low price, and high-zoom cameras for outdoorsy types. But it's at the big and small ends of the market that there's been a lot of buzz as well as a lot of players, as brands such as Canon, Nikon and Sony duke it out for market share.

The larger, "prosumer" models appearing on shelves are the digital successors to single-lens-reflex (SLR)35mm cameras (you know, the kind with interchangeable lenses). SLRs were once reserved for professionals and serious hobbyists, but a new class, priced under $700, is aimed at mainstream shooters. Not that smaller credit-card cameras have been resting on their laurels. The latest models have continued their Weight Watchers program while adding new features. How do you know which model is right for you? I tested three of each style and came up with the answers.

" USE What kind of photographer are you?

If you're going to use your camera for basic snapshots at home or on vacation, get yourself a credit-card camera. They are easy to use and easy to carry. On the other hand, if you're planning on taking some family portraits or want a picture of both little Timmy's scout troop and the sweeping mountain vista behind them, or if you plan on photographing any object that moves faster than a walk (such as your daughter in a soccer game), consider a digital SLR. Why? They just take better pictures, plain and simple. Sure, they're bulkier, but they put that extra heft to good use--if you care to use it.

" USER-FRIENDLINESS

Which is easier?

No surprises here: Credit-card cameras are meant for novices; SLRs are meant for enthusiasts. But keep in mind that most mainstream digital SLRs have a full-auto mode, which makes them as simple to use as point-and-shoots. As you get more comfortable with the SLR, it can grow with you--you can start to adjust settings and choose lenses to get the exact image you want. And user-friendliness is not just about easiness. It's also about flexibility: If you're strictly an amateur but other family members have higher photographic ambitions (a semipro spouse, a high school shutterbug), a digital SLR can work both in your clueless hands and in their more experienced ones.

If you don't know much about photography--and don't want to--get a credit-card camera. Preset shooting modes eliminate most of the guesswork: Once you remember to switch to "fireworks" or "sports" or "candlelight" when you're in those situations, you're good to go.

" PERFORMANCE

How good are the pictures they take?

All credit-card cameras can record movies, and several have other tricks, like panoramic shooting or built-in photo albums, up their sleeves. Many also have effects you can apply to photos while they're in the camera, such as making them sepia-toned or black-and-white.

But no matter how good their preset scene modes are, there's no getting around the fact that credit-card cameras have small lenses. This limits how much you can zoom into your subject--usually 3x optical magnification is all you get. Worse, the tiny lens makes it harder to take in lots of light, so in situations where lighting is dim or your subject is moving fast, the chances of getting a good shot are slimmer.

Although many credit-card cameras have six megapixels of resolution (6 million dots with which to make a picture) or more, the tiny size of the image sensor limits the usefulness of each pixel. Although this does not matter for closeups of friends and family, it can pose a problem with pictures taken at a distance. The jagged edges of a faraway mountain range, for instance, can appear fuzzy when the photo is enlarged.

By comparison, digital SLRs have really big lenses and larger image sensors, from six to eight megapixels, the better to take in the whole scene in front of you. Try shooting a sunset, especially as the sun falls behind buildings or dark hills: A credit-card camera decides there isn't enough light, so it keeps the shutter open longer; you risk overexposure, and the shot can be blurry. A digital SLR can take in enough light quickly so you get a crisp shot with rich colors and clean outlines.

Action shots--of pets, sporty kids and other fast-moving objects--are also easier with digital SLRs because they have faster auto-focus systems for crisper pictures. Make no mistake: If you want a camera that's going to take fantastic pictures 90% of the time, get the SLR. Just know that it won't have gadgety features such as movie recording or panoramic shot stitching. And most models do not offer a "live preview" of your shot on the camera's display, unlike on most credit-card models. As with an old-fashioned 35mm SLR, you still have to use a viewfinder.

" COST

What's a good one going to run you?

Decent credit-card cameras used to cost around $500 but are now dropping below the $300 mark. Among the cameras tested, only Canon's PowerShot SD630 costs more. However, its similarly performing sibling with a slightly smaller LCD screen, the SD600, can be found online for as little as $300.

Digital SLRs are more expensive, but even they are getting cheaper. Once well over $1,000, a good camera with one lens can now be had for as little as $625.

The best way to find an affordable price? Look for a model on a shopping search engine such as Froogle. Limit your results to merchants with customer ratings of four stars and up and that have reviews measuring in the thousands, not the tens. And you'll wind up with the best deal (and service) for a perfect photo finish.

Three of the newest from the most popular brands, all with six-megapixel resolution:

Canon PowerShot SD630 $375

PROS: Large three-inch LCD; nice everyday shots; power users can have some manual control; cool, iPod-like dial controller.

CONS: Were it not for the high price, this Canon might have taken top honors.

TOP PICK

Sony Cyber-Shot DSC-W50 $230

PROS: The top pick in this category. It produced the most vibrant colors and the best low-light shooting--and at a surprisingly low price.

CONS: Grainy LCD makes it hard to see what's in focus. Uses Sony's Memory Stick to store photos, rather than the more popular SD-card format.

Kodak EasyShare V603 $280

PROS: Lots of digital perks, such as panorama shooting and built-in photo organizing.

CONS: Slow to recover between shots; overpowered flash tends to wash out images.

Three major-brand models that can be bought with one or two lenses:

Canon Eos Digital Rebel XT

$780 (with one lens)

PROS: User interface is consistent with Canon point-and-shoot cameras; very good image quality.

CONS: Competitors are offering two-lens kits for the same price. Starter lens has cheap plastic feel; color LCD screen is too small.

TOP PICK

Nikon D50

$625 (with one lens)

PROS: The best one here: Almost every shot is frameworthy, and there's easy access to traditional camera controls; "help" button provides quick answers.

CONS: Uses popular SD-card memory format, which is good for most users but has a lower capacity than the CompactFlash cards used in other SLRs.

Olympus Evolt E-500

$625 (with one lens)

PROS: Lots of preset scene modes for beginners; ultrasonic dust filter removes grit from sensor.

CONS: Manual controls can be confusing; low-light performance inferior to that of Canon or Nikon SLRs.

NOTES: Virtually no camera is sold at MSRP; all cost estimates are based on prices found on Froogle.