What’s All This Megapixel, Memory, 3x Zoom Nonsense?

With all the terminology that gets thrown around in digital camera sales, its amazing that anyone gets what they want. Its so easy to be baffled by the jargon that most people give up and just trust the salesperson who often doesn’t really know much more than the confused shopper! So let me try to demystify this a little by explaining the core features of a digital camera.

Megapixel
The base component of digital photography is the pixel. A pixel is, quite simply, a point of light. A digital image is made up of hundreds of thousands or even millions of pixels. Each pixel has an assigned color so that when they are grouped together, they form a picture. The more pixels there are, the more detail. The example below shows two versions of the same picture. The one at left has twice as many pixels as the one at right and so appears much sharper. The more pixels the are, the more information the camera has to make an image sharp and clear.

When the tag on the camera refers to megapixels, its referring to how many pixels the camera will record on each shot or its resolution. A one megapixel camera will record approximately (they’re never exact) one million pixels in a picture. A 3.1 megapixel camera will record 3.1 million pixels, and so on. You may see this expressed as a ratio. For example a 3.1 megapixel camera may be explained as having a resolution of 2048×1536. If you multiply 2048 by 1536, you’ll get 3,145,728 though so it’s the same thing as 3.1 megapixels.

So how many megapixels do you need? The easy answer for me is “As many as you can afford.” It’s a bit of a cop out though so I’ll explain. The higher the resolution of the camera the higher the quality of the image. Most cameras on the market right now are at least 2.1 megapixels which is what I would say is the bare minimum for decent printed photos of up to 4″x6”. The low end standard on most of the cameras is at about 3.1 megapixels right now. That resolution is pretty good and will get you decent 4″x6” prints. At 5″x7” you’re less likely to get a real good print though. If you are interested in printing 5×7 or larger, you should look more toward a 5 or even 6 megapixel camera.

Memory

If pixels are what the camera records, a memory card is how it stores it. Digital cameras today are using flash memory which does not need moving parts to store data and can be made using very small, plastic cards.

When you buy a camera, it will come with a memory card. This card will be enough to play around with but will likely hold very view pictures taken at the highest resolution of the camera. Most come with 16 or 32 megabyte (mb) cards. As an example, a 16mb card would hold about 7-8 pictures on a 4 megapixel camera. Hardly impressive. That means you’ll have to buy a memory card.

Flash memory cards come in a few flavors currently. The popular ones in cameras now are Compact Flash, SD, XD, and the Sony Memory Stick (click here for a chart of memory card types). The camera you buy will take one of these but only one. None have a huge advantage over another but compact flash cards usually have the highest possible capacity, something that won’t be relevant unless you buy a very expensive camera. SD cards are a bit smaller and very popular in most point and shoots. XD is even smaller and popular with the ultra compact cameras. Sony uses its Memory Stick in all its cameras.

So which card should you get? First, don’t let the card type influence your decision on the camera. For most people the type of card won’t matter unless you have a shoebox full on one type at home. Second buy as large a card as you can afford. I would recommend at least a 256mb card for most people. This will allow you to take over 120 pictures on a 4 megapixel camera. A 1 gigabyte card (often called 1 gig) will hold twice as many. You might say, “Tom, there’s no way I’m taking 250 pictures of anything.” You might be right but trust me, once you are free of the limitations of film rolls, you take a lot more pictures. Add the fact that you can use the camera’s LCD screen to show off previous pictures, and you need the space. Remember this; the higher the resolution or megapixels your camera has, the larger the images it creates. That means that a 256mb card may hold 120 images from a 4 megapixel camera but it will only hold 80 from a 6 megapixel camera. Click here for an interactive chart on memory card size and capacity.

I would suggest buying two cards for piece of mind. Should something, anything, happen to your primary card on vacation or at a wedding, you’ll always have a backup if you buy two cards. The second card does not have to be as large (although that would be nice) just a good size to get you out of a jam. Additionally, if you fill up a card with tons of great shots, a backup card will allow you to keep shooting without interruption.

Zoom

One of the most important features of a point and shoot digital camera is its ability to zoom. A camera with little or no zoom will allow you to take good pictures only of the things you can physically close to. For example, you take the kids to the zoo and get great shots of them eating an ice cream cone right in front of you. They fill the picture completely. When you try to take a picture of the tiger in the back of its enclosure though, all you get is a little, striped thing in a big field of green grass.

Unless you plan to take pictures only in settings where you will be close to your subjects, consider zoom as an important factor. With zoom, the camera’s lens can focus in on a subject far away and make it seem closer. In digital cameras, zoom is measured in multiples of the base focal length. For example, most digital cameras now have a focus length beginning at 35mm. A camera with 3x zoom would have focal lengths between 35mm and 105mm. The bottom line being that the higher the number before the “x” the closer you will be able to zoom in. As I type this, 12x is about as high as you can get in a point and shoot.

How much zoom do you need? It depends on what you want to photograph. If you shoot mostly family events, something in the 3x zoom range will work fine. If you are interested in nature photography though, a 10 or even 12x zoom would allow you to close in on wildlife without having to risk spooking them by getting physically closer. Try out the camera’s zoom in the store to see what the zoom length means practically and decide what best suits your needs.

Whatever you do, do not be confused by “Digital Zoom.” Digital Zoom refers to a method of zooming in on an object by reducing the pixel count. With Digital Zoom no extra information is collected in the picture so it loses resolution. It is useless and should not be considered a selling feature. Concern yourself only with “Optical Zoom.” Optical Zoom is sometimes just called zoom but “Digital Zoom” is always labeled as such.

The Basics

So now you know you’re looking for a camera with at least 3.1 megapixels but if you want to print larger than 4″x6″ you’ll want higher resolution of around 5 or 6 megapixels. You also know what to look for in a media card. Look for two so you have a backup and shoot for around a 256 or 512 megabyte size. Finally you know that optical zoom is important for any picture opportunity that doesn’t let you get up close to your subject.

Next time we’ll take a run at the bells and whistles of cameras that can get people really confused like LCD size, anti shake features, video, and controls.