Memory cards are used by digital cameras to store photos and video clips. In this sense they perform the same role as film in a traditional film camera. There are many different types of memory card available. You need to be careful when buying a memory card to make sure it is compatible with your camera.
The capacity of a memory card is measured in megabytes (MB) and Gigabytes (GB). The number of photos you can store on a memory card depends on the number of megapixels your digital camera has. The more megapixels the lower the number of images you will be able to store.
To give you a very rough idea of capacity a 1GB card can hold 400 photos taken with a five megapixel camera, 335 with a six megapixel model and 280 with a seven megapixel camera.
A memory card is not always supplied with a new digital camera. This is because more and more cameras are being made with small amounts of memory built into them. Typically you will be able to store between five and twenty photos on the card that comes with the camera or in the internal memory. Before before you are able to do any serious picture taking you will need to buy a card with a higher capacity,
Most digital cameras are only compatible with one type of card. Others can use two, three or even four different types of card.
The most common type of card used in consumer level digital cameras is now the SD card. This type of card can also be referred to by its full name, Secure Digital. There are two reasons for the growth in popularity of the SD card. The first is its reliably small size (30mm x 22mm approx). The second is it is capable of storing large numbers of photos. The SD card is commonly found in Canon, Casio, Kodak, Nikon, Panasonic and Pentax digital cameras.
Olympus and Fuji have worked together to produce the xD card. These cards are smaller than SD cards (25mm x 20mm). All current Olympus and Fuji consumer level digital cameras use the xD card to store photos on. There are three types of xD card. These are the H card, M card and a standard card that comes without a letter. The standard card was the original xD card. The two newer types were introduced because they could hold larger numbers of photos. The H card is a higher speed card. This means photos can be stored more quickly on the card. This can increase the speed at which the camera is ready to take the next shot. The M card and the standard card are both normal speed cards.
Sony have their own type of memory card. This is known as Memory Stick. There are two types of Memory Stick. One is original Memory Stick. This is around 50mm x 20mm in size. More recently smaller Memory Stick DUO cards have made their mark. These have dimensions of 30mm x 20mm and are also thinner than the original Memory Stick. Memory Stick DUO cards are now being used as the card of choice by Sony in their digital cameras.
Previously CompactFlash cards were the most common type of memory card. Their large size (42mm x 36mm) has count against them and they are now only found in a handy of the most advanced digital cameras.
Points to keep in mind when buying a memory card include the fact that you can buy high speed cards and that there may be a maximum capacity card that your camera is compatible with. Although a high speed cards may sound like a good idea it is quite possible that unless your camera is an advanced model it will not be able to utilize the higher speed capabilities of a fast card. This is because of limitations of the technology within the camera itself. Before you go out and buy a 4GB card check with your manufacturer that your camera is capable of working with such a high capacity card.
With regard to brands I happily use cards from Sandisk, Lexar and Kingston.