What’s The Difference Between UHS-I and UHS-II SDXC Cards?

… and why do I care?

It’s all about purchasing a card that is fast enough for your video or still camera, and hopefully not buying more than you need, since everything seems to get cheaper on a daily basis.  I pulled Keith Mullin aka ‘Da Professor’ aside for a moment and asked him to explain the differences to me in layman’s terms.

The Two Card Types Are Physically Different

UHS-II cards have a second row of pins as compared to UHS-I, so they can be quite a bit faster, everything else being equal, BUT your camera needs to have slot(s) that also have the second row of pins AND their firmware needs to be able to take advantage of UHS-III to get the benefits.

Video Cameras

Currently none of the video cameras that we sell can take advantage of UHS-II cards.  The Panasonic EVA-1 does have UHS-II slots, but the second row of pins won’t be active until their much anticipated firmware update comes out this summer.

Still Cameras

The Sony A9, A7RIII, and new A7III all have two SD card slots in them:  one is UHS-I and the other is UHS-II.

Using a UHS-II card in the cameras offers no advantage for video currently, but there are rumors that 4k60p may be turned on via a firmware update for some or all of these cameras at some point in the future, and that will most likely require a UHS-II card.

For still photography, using a UHS-II card will allow burst mode shooting to continue for a longer period of time before the camera’s internal buffer fills up.  It doesn’t make the burst mode specs faster for any of the cameras, but lets you shoot in burst mode longer.


Well, there you have it.  Thanks, Keith for the info!