SD or CF Cards

Wayne sent me an email asking if his next card should be a SD or a CF. Good question!

Here’s my reply:

I visited the Sandisk site to see what they are currently offering.

–CF Cards by Sandisk: 256 GB with 160 MB/s. 128 GB with 120 MB/s

–SD cards by Sandisk: 256 GB with 150 MB/s. 128 GB with 300 MB/s (That’s fast!!)

— CFast 2.0 by Sandisk: 512 BG with 450 MB/s (Wow doggie!!)

Background Information — In the beginning of the digital photography age we had Compact Flash cards, Standard Definition cards, and some other cards that have fallen by the wayside.

Compact Flash cards, or CF cards, were for the big, new digital cameras, like the 10D and D100 made by Canon and Nikon. Standard Definition cards, or SD cards, were for the tiny point-and-shoot cameras. Tiny cameras needed tiny cards.

Then camera like the Canon Rebel came out with SD slots. Eventually, the larger digital SLR cameras came out with SD slot and a CF slot. The Canon 6D is a larger digital SLR and it only takes the smaller SD cards.

What we have today is a choice. SD cards are just as fast as CF cards. Then CFast 2.0 are on the market with reasonable prices.

Canon wrote on their site that they are not abandoning the CF cards because so many pros use them.  Good to know.

How fast of a card do you need? Do the math. Photo size x burst rate is the basic formula. 24MB raw file x 7 frames per second = 168 MB per second. That’s your starting point.

Ask also “how often do you hold the button down for 7 fps?” If the answer is often, then get a fast card. If the answer is never, then speed is not an issue when buying cards.

One last thing if you’re still with me. Buffer is also an issue. Look through your viewfinder on your camera. Push the shutter button half-way down. Look at the number is the bottom right corner or along the right side. The number might be 3 or 6 or 19 or 56. That number is how many photos the camera’s buffer (internal memory) can hold before the dreaded BUSY signal pops up and the camera stops firing. The buffer is based on the size of the photos you’re taking such as RAW or fine JPG. Bigger the photos the less photos that will fit in the buffer.