The nature of digital photography means that digital cameras have to store images differently to traditional cameras due to the physical absence of film. Instead of using rolls of film, which are then processed and developed to produce a photograph, digital cameras store their images on memory cards. The main advantage of using a card is that they are completely reusable. Simply transfer the images to your home computer, or erase them. The card is then popped back into your camera and off you go again! However, there are several types of card around, and your camera may even be compatible with more than one type. So, what exactly are you looking for?

What's Available?

As mentioned earlier, many good Digital Cameras (if not all!) are made to accept more than one type of compatible card. Unfortunately the particular one that may have been bundled in with your digital camera will more than likely be a very low capacity card, around 32Mb, perhaps even as low as 16Mb! So it won't be much use to you except as a backup. Do remember that your camera will have an in-built memory, but please don't think this a substitute for a memory card, apart from holding very few high quality images, if you have a problem with your digital camera it is likely the memory will become corrupt. You won't have the option to transfer your images elsewhere like you would if you were using a card. Here's the types of Card you can choose from:

SD Memory Card

XD Memory Card

Compact Flash Card

SmartMedia Card

Memory Stick The SD Memory card has proven a very popular in recent years, perhaps due to their small size and acceptable capacity. SD Cards hold between 32Mb and 2Gb! However, the price difference is certainly noticeable. There is a 3Gb SD Card in development, but it's unlikely to be in the high-street until next year.

The XD Memory Card is slightly newer than the SD Card, however, for all intents and purposes they are very similar in design and function. Many Digital Cameras from the Fuji and Olympus brand manufacturers favour this type of card, although the price can sometimes be a little higher. You will only find the XD memory cards with a 1Gb capacity, but to be honest unless you're a professional Photographer taking hundreds of shots per session, you won't need anything bigger, you simply wouldn't fill it up!

A Compact Flash card is an alternative method to store your images. At around an inch in size, CF Cards are used more and more. Because they are sold in a solid form, meaning no moving parts, they are robust and reliable. CF cards also come in substantially greater capacities than the previous two types and are available even up to 8Gb!! Some manufacturers produce not only differing capacities but also differing speed cards. This allows for images to be recorded quicker which allows the photographer a faster follow on shot. If your serious about digital photography, or need storage in a professional sense, a CF card is your best option.

SmartMedia cards have been in the Digital Photography market for a long time, they are reliable, reasonably priced and come as standard. However, of late, SmartMedia is quickly becoming sidelined for newer more advanced options of image storage such as the Compact Flash cards discussed above. You may find that your Digital Camera isnt compatible with SmartMedia Cards anyhow. Always check your manual for compatibility before parting with your cash!

Last but not least we have the Memory Stick. Originally used primarily in Sony cameras, you may recognise Memory sticks from other devices such as your mobile phone or personal computers. Again, Memory Sticks are available in several capacities and are also available from different manufacturers. As far as Digital Photographers are concerned, Memory sticks are legitimate options for storing images, however they are slightly more prone to becoming damaged due to Memory sticks being physically more frail than its Compact Flash counterpart for example which has a more solid and hardened plastic body.

What size Memory Card do I need?

That's a difficult question to answer in general terms as it depends on the Photographer, the camera you are using and for what purpose your photography serves. Let me explain..

Each and every digital image is made up of pixels, these together will eventually add up to a Megapixels. These large files are measured in Mb (Megabytes), so the more Megapixels your camera has, the more Megabytes you'll need to use to store it. To make sure your camera uses the Megabytes in its memory effectively it uses a process called 'compression'. You may have heard this term before. It is a shrinking process that ensures the memory card you are using fits as much on as possible. On some cameras this compression rate can be set manually, but beware that although higher compression rates mean you can fit more on, it also degrades the picture quality too. Find a happy balance, or better still, let the camera automatically set the rate.

You will notice that higher Megapixel cameras produce better image quality, but use more space on memory cards per shot. Therefore think carefully about how many images you would like to store at any one time, then check your cameras Megapixel rating. For example a 16Mb memory card would hold around 16 or so high quality images from a 2 Megapixel camera, but only around 6 from a 4 Megapixel camera. I would recommend purchasing a 64 Mb card, which would mean you won't ever find yourself missing a shot while fumbling to delete images to free up space!