Have you looked at your memory card lately? I'm not making a value judgment. I never gave a second thought to looking at a Secure Digital(SD) memory card or the packaging.
I usually looked to see if it was a SD or a Secure Digital High Capacity (SDHC) card, what was the capacity and how much did it cost. Ah, but one day my eyes dropped down and looked at the packaging. I saw the word class.
What Does That Mean and Why Should I Care?
I went to the SD Association website and I got an answer. Memory cards are designed for specific purposes and products.
For example, the memory card in your cell phone might operate at a different speed than the one in your camcorder. They could both be 4GB cards but one will work faster than the other.
The class number refers to how fast data moves from the device to the card.
The symbols on the package tells the story. This memory card is specifically designed for photography and camcorder use. It is a high capacity card. Not all devices accept these cards. You do have to check the camera specifications to make sure. This memory card in the photo is a Class 4 card which means that it has a data transfer speed guaranteed at 4MB per second.
So if your camcorder has a transfer speed of 6MB per second or a Class 6 card and you stick a Class 4 card it will work but you are not using the full recording ability of your camcorder.
Real World Test
So you are looking at the weekly Fry's or your are standing in Office Max. There is a sale on memory cards; 16GB for $8. You are thinking, score. Except why is the card selling so cheap? It could be a store brand. It could be a closeout of a prior version. That is why you should take the time and look at the packaging.
Older SD cards will have speeds like 50x but they will not have a class number. Your device may or may not accept the older version of a SD memory cards.
SDHC memory cards will have a class number and on the packaging generally the suggested use of the memory card.
One More Thing
SDHC cards do not play nice with older computer SD memory readers and older memory card readers. You might need to buy a SDHC reader. So know your equipment.
Bottom line, if there is a sale there is nothing wrong about buying a slower SDHC memory card just understand it might affect your camcorder recording performance.