The resolution of an image is determined by the number of pixels, or tiny dots, contained within it. The higher the number of pixels, the greater the clarity and color gradations of the image. Digital cameras are categorized by their resolution, which is measured by how many megapixels (1 million pixels) they can capture with each image. The resolution is one of the single most important factors in selecting the right camera for you.
The number of megapixels will determine how large you may print an image before it begins to break down and appear grainy or "pixilated". A general rule of thumb correlates megapixels to maximum print sizes as follows:
- <1 Megapixel - Onscreen images (display on web or email) or very small prints
- 2 Megapixel - Quality 4x6 prints on desktop printer
- 3 Megapixel - Quality 8x10 prints on desktop printer
As the megapixels increase, so does the stored file size. If you plan on taking many high-resolution pictures in a single session, be sure to have plenty of storage media to save them all. If you plan on editing these high-resolution images on your PC, you'll want to have adequate disk space and RAM available. Most high-resolution cameras, however, provide the option of adjusting the resolution downward whenever you do not require a larger image, such as when shooting images for the web or for email.
Zoom is measured by how many times closer the image appears, so a 3x zoom will magnify the subject of your image three times. Since photographers are often further from subjects than they'd like to be, zoom is a critical function of any camera.
Optical Zoom vs. "Digital Zoom"
Optical zoom, sometimes called "true zoom", is achieved by moving the camera lens, just as one would on a 35mm camera. Using optics to zoom in allows you to take pictures that appear much closer, without any loss in picture quality. Today's digital cameras range from a fixed lens (no zoom) to 10x optical zoom in higher-end models. An average digital camera will sport a 3x optical zoom. The greater the optical zoom available, the more options you will have in framing a shot to your preferences.
Digital zoom, on the other hand, is simply an electronic manipulation of the image by the camera's processor. Essentially, the camera takes an image and uses mathematical interpolation to fill in the blanks and "guess" at what the picture should look like when zoomed. The major drawback to this method is pixelation, or the appearance of tiny dots throughout the image that decrease sharpness and resolution. Those using this method to zoom-in are often quite disappointed by the fuzzy and muddy images that result. These same digital effects can usually be rendered more reliably by photo editing software programs, which offer far greater control of the manipulation of images.
Generally speaking, digital zoom features are little more than a marketing concept and should be disregarded when making a decision in selecting a digital camera.
For those familiar with SLR photography, digital camera specifications usually list the 35mm equivalents for digital camera lenses. This may be helpful in determining which camera has a lens that approximates the focal lengths you are used to.
While the LCD viewfinder is one of the most used features of a camera, it is frequently overlooked when selecting a digital camera. The ability to preview what the camera sees before you take a shot can be critical for capturing the best possible images (and spotting flaws in images you've just taken, allowing you to re-shoot). Obviously, the larger the LCD screen, the larger the preview image you will have to work with. Of course larger screens will add to the size and weight of the camera, so trade-offs have to be made. Additionally, the LCD screen is one of the primary drains on power, so a larger LCD means a higher power usage and more frequent battery changes.
Another feature of LCD screens that may be particularly useful if you plan on taking any outdoor shots is the ability to swivel the screen. Cameras with this feature allow for redirecting the screen away from sunlight (so it doesn't get too washed out to view) while keeping the camera pointed at the subject. This prevents having to take a "blind" shot in direct sunlight conditions.
There are two ways of uploading your images from your camera to your PC. All digital cameras come with some method of direct connection that usually involves a serial or USB cable. The alternative is to connect a media card reader, which allows you to take the media out of the camera and plug it into the reader, which then uploads the images.
Direct Connect- Serial vs. USB
There are two common direct connection methods, serial and USB. The differences between the two are speed and ease of swapping. USB connections will greatly reduce the amount time it takes to upload images from your camera and can be swapped out while the computer is running (as opposed to requiring you to shut down your computer and reboot) which is very handy if you are sharing that connection port with other devices. While USB ports are widely available on newer computer systems, older systems may only have serial. Be sure to check the ports on your system and select a camera compatible with your system.
Card readers offer the convenience of reading images directly off the card, without having the camera attached. This allows you to conserve the batteries of the camera during uploads, and, if you use multiple media cards, you can upload images off one card while shooting images on the other. Like direct connect, card readers can be set up as serial or USB, and must be matched with the ports on your PC.
Most cameras will come with some minimal amount of internal memory and/or a very small memory card. However, the amount of images you can store with this memory will usually be quite limited, which means that you will need larger external memory cards to be able to take several pictures between uploads. There are four primary types of external media.
Compact Flash, SmartMedia, Multimedia and MemoryStick
There really isn't any inherent advantage between these formats, and the picture quality should be the same regardless of format. Older cameras that use SmartMedia cards may not accept some of the newer high capacity cards, so if you are upgrading an existing digital camera, you may want to see if it can read a larger card.
The size of the media card, which is measured in megabytes (MB), will determine how many images will fit on it before it is full. Once it is full, you cannot take any more images until you delete some (which is usually done after you upload images you wish to keep).
Since a larger card means you can store more images, you should opt for the largest card you can afford. The different media formats currently have vastly different maximum capacities. Compact Flash supports a capacity of 1GB (1,000 MB), Multimedia reaches 256 MB while MemoryStick and SmartMedia max out at 128 MB.
The size of the images you take will determine the minimums you will be comfortable with. If, for instance, you plan on only taking low resolution images for the web or emails, a 16 MB card may be adequate. If you are using a high resolution camera, however, you may need a 256 MB card (or higher) for sufficient storage. As with all types of storage decisions, it is always better to overestimate your requirements than to end up needing more capacity.
Digital cameras have three power options. Some cameras come with a proprietary rechargeable battery. Others use AA batteries, which can either be standard single-use alkaline or rechargeable NiMH batteries. Since digital cameras use up batteries so quickly, it makes economic sense to use rechargeable batteries instead of normal alkaline AAs.
Proprietary and NiMH batteries
There are advantages to cameras that use proprietary and those that use AA size batteries as well. Proprietary batteries can often be recharged in the camera itself, which is very convenient. However, the downside is that, since it uses a unique battery, you cannot run out to the corner store and grab a pair of batteries off the shelf in the event you want to use your camera when your proprietary battery is run down.
Extra pack and charger
Regardless of the type of battery the camera uses, you will probably want to invest in a spare set of batteries with a charger. Since they can drain batteries quickly, if you don't have a spare set charged and ready to go, you will likely face frustrating situations where you miss out on using your camera because the batteries are dead. If the camera has a battery charger built in, you will still want the separate charger, so one set can recharge while you shoot.
"Gray Market" Products
As with all consumer electronic equipment, there is a huge gray market for digital cameras, especially on the internet. Gray market products are those made by a popular, reputable manufacturer, and intended for and shipped to a foreign market. They are purchased by a dealer that accepts gray market products, and then resold in the US, usually at a discount. Most of the "great deals" you find on the internet are gray market products.
Aside from manuals and menus that may not be in a language you even recognize, and cords that won't plug in to American systems without some adapter, these purchases maintain one overriding risk. They do not come with a US warranty from the manufacturer. This means that if something, anything, goes wrong with that camera, you may be completely out of luck. In fact, some manufacturers will not service gray market cameras in the US at all, even if you are willing to pay for it yourself. So if you want to get that camera fixed, it may require shipping it to a foreign country and hoping for the best.
The easiest way to spot a gray market deal is to look at the included warranty. Many gray market sites will either offer a "manufacturer's warranty", which will only be good in the country of origin, or a "US warranty" , which is merely an aftermarket warranty provided by the company running the website. If you don't see both of these components together, chances are it is gray market. Also look (in the fine print) for phrases that talk about "may be missing some original packaging, cables, etc.". Dealers that operate on the level receive their products packaged complete from the manufacturer, and you should be wary of any that don't sell their products the same way.
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