what does the different speed on an sd memory card mean?

Question

i am looking to buy an sd card for my dslr, what is the difference between the speeds and which is best?

Answer 1

Here's an answer that I wrote for a specific application, but it will be useful to you in your buying decision:

Sandisk makes some nice higher speed cards in SD format (and others) with a lifetime warranty. The Ultra II is "mid range" high speed and Extreme III is ultra high speed. We have an Extreme in my wife's D50 and never had a problem with write speed. Click, click, click, click, click, click, click, click.....

The benchmark of 1X is a transfer rate of 150 KB per second.
40X is a common card, so the transfer rate would be 6 MB per second.
Sandisk Ultra II claims a minimum write speed of 60X or 9 MB per second, and a minimum read speed of 66X or 10 MB per second.
Sandisk Extreme III claims a minimum write and read speed of 133X or 20 MB per second.

The largest 6MP photos on a D50 camera seem to be about 3 MB, so it seems that an Ultra II could save 3 high data images per second, while an Extreme III could save 6 high data images per second. The D50 continuous mode gives up to 2.5 frames per second, so you could be gathering about 8 MB of data per second. If you do not have at least the Ultra II or equivalent, it is easy to see how your D50 bogs down at times.

Answer 2

Faster cards can take the image you just shot and put it into their own memory more quickly. If you like to take photos one after another that will be important because you can't do the second picture until the first one is stored.

If you camera has an internal buffer that stores an image before the card gets it then it doesn't make any difference. Even a slow card will be loaded with the image before the buffer will keep you from taking the next picture. Most DSLRs have that internal buffer so it is not an issue for you unless you quickly take lots of consecutive photos. Most people don't.

Answer 3

It depends on your camera. The speeds listed on the card relate to write speed from the camera to the card. If you have a fairly new top of the line DSLR it will take advantage of the faster write speeds ortherwise it depends what your camera's maximum write speed is. Check your camera technical specs that way your not paying extra for something you can't use. If your not a pro shooter or not shooting fast action sports or such, the slower cards that are discounted will work fine.

Answer 4

possibly between the greater suitable motives of memory card errors isn't correct dis-mounting the cardboard from the workstation, removing it while the digicam is on, or while a gadget is writing to the cardboard, etc. No card can stay away from the consumer from doing dumb issues.

Answer 5

The faster the speed, the quicker it writes, and so the sooner it is ready to take the next picture.

Answer 6

they go and bought their own thin lol