SDHC Memory Cards for Cameras
While many high-end professional DSLR cameras primarily use CompactFlash (CF) memory cards, the Secure Digital (SD) format of memory card for cameras has become the most widely used.
This type of card can be found in the simplest of compact cameras, as well as in the second slot position of many professional DSLR cameras. They are compatible with the majority of digital cameras and they are also found in many camcorders, with the exception of older Sony models.
Not all SD cards are the same and it's important to know which to choose, both for compatibility with your camera and also to gain all the benefits.
SDHC
The first kind of SD cards were capable of storing up to 2GB of data. This was more than adequate in the early days of digital photography, but soon became a limiting factor as cameras produced higher resolution files.
SDHC (Secure Digital High Capacity) memory cards are able to store much more data than SD, whether still images or video.
SDHC cards were created to go up through 4GB, 8GB, 16GB to 32GB. They are identical in shape and size to SD cards, but if an SDHC card is fitted into a camera made before the arrival of SDHC the card may not be identified as greater than 4GB and may not be recognised at all.
Some low cost camcorders may accept SDHC cards, however the device will only identify them as 4GB even if they are in fact of higher capacity. It is important to check the camcorder's specifications to see if this is the case.
Speed of SDHC cards
Not all SDHC cards are of the same speed, which is the measurement of how fast the camera or camcorder can write data to the card. There are four classes - Class 2, Class 4, Class 6 and Class 10.
Class 2 cards offer a minimum sustained data rate of 2 megabytes per second (MBps), Class 4 of 4MBps and Class 6 of 6MBps and Class 10 of 10MBps.
For standard definition camcorders, or the average camera, an SDHC card with a Class 2 speed is normally sufficient.
However, for high definition camcorders as well as high performance DSLRs, a Class 6 card may be better, while a Class 10 card may be better still. However, if the camera or camcorder is not particularly high performance it will be a waste of money to invest in Class 10.
It's important to therefore check the camera or camcorder specifications before making a choice.