When it comes to CF cards, or any memory card for that matter, there are two important things to consider, size and speed. On a CF card storage size is usually prominently displayed on the front. At this point in time, CF cards come in a wide variety of sizes from 4GB to 512GB – quite a range in storage space!. Prices range anywhere from $10 to $900 depending on the size and speed of the CF card.
Most CF cards display the read speed (the speed at which a computer or device can get information off the card) on the face of their cards. This is important, but for filmmakers or photographers the number that really matters is the write speed (the speed at which information can be written onto the card). The write speed is always slower than the read speed. However, nicer cards typically have a write speed that is closer to the read speed.
CF cards don’t always write at the same speeds either. So be sure to check both the minimum and the maximum read/write speed with your card. Just because your card can write up to 95mb/s doesn’t mean it can sustain that write speed for an extended amount of time.