Memory cards explained: speed classes and reliability

Memory cards store your work and affect how fast your camera performs.

SD speed ratings

• UHS-I vs UHS-II: UHS-II cards have an extra row of pins and are much faster.
• Video speed class: V30, V60 and V90 indicate minimum sustained write speeds of 30, 60 and 90 MB/s.
• For 4K video at high bitrates, use V60 or V90.

CFexpress Type A

Sony cameras like the A7R V accept CFexpress Type A for the fastest bursts and highest bitrate video.

Capacity

Several 64 GB to 256 GB cards are safer than one huge card. If one fails, you lose less.

Dual slots

Record to both slots simultaneously for important shoots.

Care

• Format cards in the camera, not on a computer.
• Do not delete images in camera during a shoot; it increases corruption risk.
• Replace cards every few years.
• Store them in a protective case.

Buy genuine

Counterfeit cards are common online. Buy from trusted sellers.