Guide to buying a cheap camera

The excellent Panasonic SZ7 is a steal at about $99, nearly $100 less than its original price.

(Credit: Sarah Tew/CNET)

It seems like every year there's a glut of point-and-shoot cameras getting put out at ridiculously low prices for the holidays, all touted with the same three specs: megapixels, zoom, and screen size.

It's understandable, too, since those are things manufacturers and retailers can attach larger and larger numbers to and people will think they're getting a better camera. However, just look a little more closely at those specs and they could make the difference between a winner and a loser.

So, if you're going to pick up a camera based mainly on price, do yourself a favor and take a quick look at some key things to see if what you're getting is actually a good deal.

Megapixels
To paraphrase CNET's camera buying guide, having more megapixels does not necessarily mean better photo quality. This is especially true for inexpensive pocket cameras, where it's cheaper and easier for manufacturers to ratchet up the resolution to sell cameras than to improve image quality in other ways. So if you're trying to decide between a 16-megapixel camera and a 12-megapixel one, don't let the extra resolution sway you because it's not a guarantee of better-looking photos.

What you can look for is the type of image sensor it uses. Most point-and-shoots are capable of taking good snapshots outside in good lighting. Head indoors or under darker skies, though, and things can get nasty really fast. If low-light shots are superimportant to you, you'll want a camera with a BSI (backside-illuminated) CMOS sensor. They're designed for better image quality when you have less light and also have the side benefit of speeding up shooting speeds. It'll cost a little extra, but can make a big difference. A quick check of a camera's specs on the manufacturer's Web site will confirm if the model you're interested in has this type of sensor.

Unless you're doing all of your shooting in daylight outdoors or under a lot of light indoors and don't mind slow shot-to-shot times, you'll want to skip inexpensive cameras using CCD sensors. The one exception I make for this is Canon's A-series models. Their high-ISO image processing (needed for low-light photos) is typically better than you get from similar cameras from other manufacturers.

Zoom lens
One of the big reasons to get an inexpensive pocket camera is for its zoom lens. Even most sub-$100 models have some optical zoom, but there is more to a lens than just the number next to the big "X." You'll want to look at two other specs: focal length and aperture range.

The focal length is basically the range of the lens, from wide to telephoto. Wide lenses capture more of a scene, which makes them nice for group shots and landscapes. Look for a starting point of 30mm or wider (which for focal length would be a lower number, such as 28mm). Multiply this number by whatever the zoom factor is for the camera and you'll get the telephoto focal length; for example, a 30-300mm lens is a 10x zoom.

As for aperture range on a point-and-shoot, I'm not going to get into a full explanation here (feel free to hit Wikipedia for that). What you should look for, though, is a set of two numbers designated with an f and presented as a range, such as f2.8-5.9. The first number is the maximum aperture at the wide end of the lens, the second number is the maximum aperture at the telephoto end. Basically, the lower these numbers are, the better off you'll be. In the example I gave, an f2.8 aperture is very good, but the f5.9 -- though typical of point-and-shoots -- is not. Overall, though, that's not as bad a range as f3.2-6.5.

Another thing to look for is what type of image stabilization a camera uses, because cheaper cameras generally have electronic image stabilization only, which affects performance and photo quality. Look for optical or mechanical (also called sensor shift) stabilization.

Screen
Retailers pretty much stick to one spec when it comes to viewscreens: size. The standard size on lower-end cameras is 2.7 inches. Anything larger than that sweetens the deal. You'll also want to check resolution, which should be at least 230,000 dots. Higher than that, again, is a bonus.

You will find cameras with smaller, lower-resolution screens, and you can tell the difference. And, of course, not all LCDs are created equal, so if possible you'll want to test out viewing angles and brightness before you buy. This goes double for touch-screen models because responsiveness tends to be an issue on budget cameras.

Lastly, many models use wide-screen displays, which sounds OK, until you realize you won't have use of the entire screen when framing your shots unless you're shooting in a wide aspect ratio like 16:9; a 4:3 aspect ratio is usually the default. That can quickly turn a 3-inch screen into one barely more than 2 inches.

The difference between Sony's WX100 and WX150: screen size.

(Credit: Sarah Tew/CNET)

A note on 'exclusive' models
In order to get consumers to come to a specific store for an item, manufacturers will give the store an exclusive model. This is not new or unusual, but with cameras it can be very confusing because the differences aren't always clear. It can be something as basic as an exclusive color, but in other cases they'll strip or add features, which may make or break a purchasing decision for you.

For example, the Sony Cyber-shot DSC-WX150, an excellent 10x zoom ultracompact, is widely available and sells for as low as $200. However, Best Buy has an exclusive model (for the U.S. at least), the WX100, which it is selling for $160. The key difference between the two models is screen size; the WX150 has a 3-inch LCD whereas the WX100 drops to 2.7 inches.

Similarly, the Panasonic Lumix DMC-ZS20 and DMC-ZS19 are the same camera, but the former has built-in GPS for adding location information to your photos. That's nice to have if you travel frequently but may not be worth the $30-$40 price difference between the two models.

Basically, if you were interested in a specific camera and you see one with a similar model number, do yourself a favor and double-check the specs to make sure you won't be sacrificing a key feature.