The purpose of this guide is to help new or less experienced digital camera users better understand digital memory and digital memory cards, to help improve their overall experience of using a digital camera. This guide has been updated by Linda's Camera World (lindas_camera_world on ebay), as of Summer 2007.

As traditional 35mm images physically used space on a roll of film, digital images take up electronic space on a digital camera.  The space used is a called a bit or byte and a typical digital image today can take up to 1 million bites (1MB or 1 Megabyte) or more, per digital photo.  Additionally, recording digital video clips is easy with most point and shoot digital camera models, but recording video uses megabytes of memory at even higher rates than images.  The amount of memory a digital camera can hold, or be expanded to hold through the use of memory cards is extremely important to digital camera users of all skill levels.

What is Internal Memory?
The average digital camera sold today may include 8-32 Megabytes of internal memory.  This digital memory space can be used for storage of images; however it is not removable or expandable, and is located inside your camera.  This is a nice feature of some digital cameras as this space allows you storage of a few photos and can be perfect for keeping a small photo album in your camera, or for snapping a few extra images if your expandable memory card fills up.  However, based on typical resolution settings an average digital camera user may use up all the cameras built in memory with only 5-20 photos or 15-20 seconds of video. This memory source is not well applied for mass storage of photos or videos, and the main reason most quality digital cameras in production today include an expandable memory card slot.
 
How Do I Expand My Digital Cameras Memory?
The ability to add removable storage for digital images and video is common in today’s digital cameras, and most digital cameras in production today have something called an expandable memory card slot built into them.  This slot allows the user to add a small card, purchased for an additional cost, for storing larger amounts of digital pictures or video.  An expandable memory card can hold 500-1000 or more digital photos, or 1-6 hours of digital video or MPEG4 Movies. 

Do I Need a Memory Card for My Camera?
For typical applications of a beginner or novice digital camera user, I would highly recommend use of expandable memory cards.  Most of these cards can be purchased for under $50, and will allow you to expand the amount of pictures you can store at one time to over 1000 photos, and even allow you to hold 1-6 hours of digital video! 

What Size Expandable Memory Card Should I Purchase?
Expandable memory cards can range in size from as small as 16MB, all the way up to8GB (8 Gigabytes or 8,000,000,000 bytes / 8 billion bytes), and range in price from $10-$200. The most commonly used and the sizes recommended for digital cameras range from as small as 256MB, to the larger 2GB size cards. The chart below will give you a basic outline of how much memory a digital image will take up on different size cards, and with various output resolutions.  Please remember these are approximate numbers of images; results with your camera may vary.

                                Resolution / Mega Pixels
Capacity     3.0 MP      5.0 MP      8.0 MP   10 MP  12 MP
256MB      300             240           160           110          71 
512MB      600             480           320           225         121
1GB         1200            950           600           400         260
2GB         2400          1900          1200           800         500
4GB*        4000          3000          2000          1500      1000

I find the useful range of sizes of memory cards to be between 256MB if you don’t record or plan to record a lot of digital video, and no smaller than a 1GB card if you do.  Overall I recommend using no smaller than a 256MB card. At this size you may find you will need to download (transfer) the pictures after one (1) day of typical sightseeing or normal family activity or trips, the larger 1GB, and 2GB cards may offer enough room for storing pictures for an entire vacation or holiday.  *Note, 4GB ,8GB and even now 10GB cards are now being sold, however these cards are not recommended and they are currently moderately to very expensive, and not always compatible with all models of camera. Most camera models will only accept a maximum 2GB card.
 
What Type/Format of Memory Card Should I Use?
Memory cards come is a few different digital formats and it is important to know what type of card your camera uses. I have found that most basic point and shoot digital camera models now use Secure Digital / SD Memory Cards.  Advanced photographers have some uses for Compact Flash / CF Memory Cards; and XD Memory Cards™ and the Sony Memory Stick™ are proprietary to a few of the name brand digital camera models. I have included some additional information to help guide you below.

• SD Card Technology. Secure Digital (SD) card is the most commonly used card for advanced point and shoot digital cameras.  It can also be used in a variety of other commonly used digital products such as MP3 music players, Pocket PCs, and digital video camcorders.  SD cards are also being used in advanced applications such as the new 'smart phones', cellular phones, car navigation systems, electronic books and more.  The SD Card is a highly secure stamp-sized flash memory card, and was jointly developed by Matsushita Electronic (best known for its Panasonic™ brand name products), Lexar™, PQI™, Sandisk™ and Toshiba™ are commonly sold name brands of the SD card. The SD Card weighs approximately two grams with a compact 32.0 x 24.0 x 2.1 mm size. As of early 2007, computers that use SD memory in addition to hard drives (and in some cases in place of), are being tested and sold for the first time.
  

• xD Card Technology.  The Olympus xD-Picture Card™ are compatible most only with Olympus, and some Fuji cameras. Ultra-compact size: 20.0 x 25.0 x 1.7 mm.
  

• Memory Stick Technology.  Sony Memory Stick™ products are compatible most only with Sony cameras and devices. Longer thin size: 21.0 x 50.0 x 2.8 mm.
  

• CF Card Technology.  These larger sized, larger capacity cards are better for professional photographers who often prefer to shoot large image files, such as TIFF and RAW, and have a need for high-speed, high capacity memory cards.  The superior 40X-speed cards are guaranteed to be capable of a minimum sustained write speed of 6MB/s, and may operate up to a maximum write speed of 7MB/s or more. Used in some SLR. Larger, 36.4 x 42.8 x 3.3 mm size.
  

One of the best ways to find out what type of memory card your camera uses is read the specifications of the camera.  Additionally, a responsible camera manufacturer or retailer will make that information easily available to you as a memory card is generally not included with a camera purchase, but are necessary options to fully maximize the performance of your camera. Learning to use a digital camera and its extra features can be challenging, and expandable memory cards are a great way to help get you started using one of the lesser known, yet highly effective and enjoyable features of a digital camera.

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