Understanding your Memory Card

Memory cards are often confused with others forms of media storage, such as hard drives and floppy disks. A memory card works differently than other forms of media storage, and understanding the difference may save you from losing precious memories that are stored on your camera's media.

Here are two crucial bits of information that every digital camera user needs to know in order to assure the safety of their images.

1. Turn Off Your Camera: First, remember to always turn your camera off before removing or inserting a memory card. When your camera is on and your card is inserted the two are interconnected, passing information in the form of magnetically charged particles. Yanking out your memory card can literally cause things to go haywire.

2. Format Your Card: Second, format your card regularly and always do so while it is in your camera, not connected to your computer. In fact, not only should you not format your card using your computer, but you should not even delete individual files with your computer.

The problem with erasing or formatting memory cards on your computer is that your computer works differently than your digital camera. The ways in which these tasks are accomplished by the two machines are different, and in many instances the two machines may be incompatible.

You can save yourself and your memory card from potential scrambled data, i.e. irretrievable photos, and ensure your ability to take pictures when you want to by simply following these memory card care guidelines above.

Resolution Requirements

To figure out what size prints you can make from your digital camera, you have to break down the pixel measurements of your camera.

• a 4.1-megapixel camera works out to a picture with dimensions of 1704 x 2272 pixels at its highest resolution.
• a 3.34 megapixel camera works out to 1536 x 2048 pixels.
• a 2.24 megapixel camera works out to approximately 1280 x 1600 pixels.

For a reasonable quality print you need approximately 150 pixels per inch of resolution (we'll call this medium quality), while for professional quality prints you need at least double that. For simplicity's sake, pick either the long or short dimension of the print/camera resolution and work with that one. For this instance we'll use the long edge of the print. Let's work through a couple of examples:
 
2.24 Megapixels
Maximum print size (medium quality) for a 2.24 megapixel camera: 1600 divided by 150 = 10.7." Using this example, you could get a medium quality print of up to about 10 inches (so you could get a medium quality 8"x10")

Maximum pro quality print size would be 1600 divided by 300 = 5.3". In this case, you'd be able to get a pro quality print at 3.5" x 5".
 
3.34 Megapixels
Maximum print size (medium quality) for a 3.34 megapixel camera: 2048 divided by 150 = 13.65", so you'd be able to get a medium quality print of close to 11" x 14".
 
Maximum pro quality print size would be 2048 divided by 300 = 6.8." In this case, you'd be able to get a pro quality print at 5" x 7."
 
4.1 Megapixels
Maximum print size (medium quality) for a 4.1 megapixel camera: 2272 divided by 150 = 15.14", so you'd be able to get a medium quality print of close to 11" x 14" with the option of cropping an inch around the edges to emphasize your subject some more.
 
Maximum pro quality print size would be 2272 divided by 300 = 7.57." In this case, you'd be able to get a pro quality print at 8" x 10" with a border.
 
Keep in mind that these guidelines are not absolute! Your lens, lighting, CCD quality and method of printing all play a part in the final results. Also, the resolutions quoted are based on optical resolution and not interpolated (upsampled) resolution. The formulas can be applied to cameras of any resolution, or you can work the formula backwards to find out how many megapixels are required to get the image quality you require at the size you will be printing. Good luck!

Photo Resolution Chart

The following chart can be used as a guide to help you decide what resolution camera you should purchase, or what resolution you should use when taking digital photographs.