Choosing the right digital camera

With so many choices available in the market, it is essential to understand some of the features of a digital camera in order to find one that suits your needs.

a) Sensor resolution

At the heart of every digital camera is a sensor, the electronic chip that takes incoming light and converts it to a digital file. Most digital cameras use a charge coupled device (CCD) sensor, while low-cost "entry-level" cameras (including webcams) use a complementary metal-oxide semiconductor (CMOS) sensor. CMOS chips are easier and cheaper to make, but they often do not match the picture quality of a CCD.

Resolution refers to the number of pixels in a picture, that is the small dots that make up an image. The more pixels there are in a picture, the higher the resolution, therefore the sharper the image. You can calculate the resolution of an image by multiplying the number of pixels on the length and width. For example, a 2,048 x 1,536 image is 3.14-megapixels (2,048 x 1,536 = 3,145,728 pixels or 3.14 megapixels).

However, it is important to note that a 3.34-megapixel camera does not mean that the highest resolution image that can be captured is 3.34-megapixels. The actual resolution -- (also known as the effective pixels) -- is in fact lower, at only 3.14 megapixels (keeping to the 4:3 aspect ratio).

Most entry-level digital cameras come with a 1.3-megapixel (1,280 x 960) CCD sensor. These are good for taking pictures for web publication and reasonably large enough for 5 by 7-inch prints. For 8 by 10-inch prints, a two-megapixel (1,600 x 1,200) camera is recommended, while three-megapixel (2,048 x 1,536) ones are capable of decent prints of up to 11 by 14 inches.

In the past few months, four- and five-megapixel cameras have begun appearing in the market, bringing down the prices of the three- and two-megapixel models. We�d advise you to get a camera with a minimum of two megapixels, as the higher resolution allows for cropping, while still maintaining a high quality image.

Note : You may have heard that Fujifilm has digital cameras capable of capturing images up to six-megapixels. Unlike the professional cameras like the Nikon D1x or the prosumer Minolta Dimage 7, which are equipped with 5.24-megapixel CCD sensors, these Fujifilm cameras use digital interpolation to achieve that resolution.

b) Optical and digital zoom

Cameras have either optical zoom and digital zoom. In optical zoom mode, the camera moves the lenses back and forth to enlarge or reduce the size of the subject, while digital zoom merely involves taking part of the picture that the lens has captured, digitally enlarging it, and throwing away the rest.

The end result is that the picture captured using digital zoom is actually of lower quality, since it is based on a blown-up fragment of the image. In other words, digital zoom is simply another form of cropping, and we don�t advise you to use it or buy a camera that only has digital zoom.

A 2x or 3x optical zoom would be ideal for most purposes.

c) Storage

CompactFlash (CF) Type I and II, SmartMedia (SM), MultiMediaCards (MMC), Secure Digital (SD) cards and MemorySticks. These are the most popular flash memory cards that are used in most digital cameras today. Basically, they all serve the same purpose, which is to store the captured digital images. The only difference between them is their size and price.

The two older formats, the CF and SM, are cheaper and larger-sized than the others. One piece of 64MB CF costs about US$40, but a similar capacity MemoryStick easily costs twice as much.

Since most cameras come with only a 8MB or 16MB, the type of flash memory used would be an important consideration. You would probably need an extra memory card and an expensive format may blow your budget. (A 16MB card holds roughly 32 pictures at 1600x1200 resolution using normal JPEG compression.)

Right now, only CF (Type I and II) cards are available in capacities higher than 256MB, although the other formats are expected to release larger capacity memory cards later this year. It should also be noted that CF is available in two formats. Type I cards refer to the standard CF cards while Type II cards are actually small hard drives (e.g. IBM's MicroDrive) that can store as much as 2GB of images.

There are also other storage media such as CDR/RWs and floppy disks that are being used in digital cameras. However, these cameras tend to be generally bigger in size (due to the media) and are not as common. Their main advantage is their cheap, re-usable media and convenient transfer of images to the PC.

d) Batteries

Most digital cameras use either two or four AA-size batteries, though there are others that are powered by a lithium CR-V3 battery or proprietary rechargeables. Some use all three types.

Due to their high power consumption, it's advisable to get cameras that use disposable batteries which can be bought anywhere. This way, there are no worries when the battery runs out of juice.

You may also want to consider investing in a set of rechargeable Metal Nickel Metal-Hydride (Ni-MH) AA-size batteries instead of throwaway alkaline ones. On the other hand, if the camera uses only proprietary battery packs, think about getting a backup pack, for use on longer trips.

e) LCD

The liquid crystal display (LCD) is probably the most looked-at -- and the most power-draining -- feature on the digital camera, either as a viewfinder or for playback and menu access. Therefore, it is important to ensure that the camera you buy has a sharp, bright and sufficiently large LCD screen. A screen of at least 1.8-inches diagonally is recommended.

f) Viewfinder

Besides the standard optical viewfinder found on most cameras, some of the higher-end models like the Minolta Dimage 7 come with electronic viewfinders. These are actually smaller LCDs that repeat the image found on the rear camera LCD, and are generally thought to be more accurate than an optical viewfinder.

« 2. Matters of money | 3. Frills or key features? (cont'd) »

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