Sony A9 II SD Memory Card Requirements

Nathaniel Stephan
May 31, 2025

Table of Contents

The Sony A9 II has two UHS-II SD memory card slots. Both slots can use SD cards with a maximum capacity of 2TB.

Get a UHS-II card with at least a V30 rating for 4k video or for continuous shooting at 20 fps.

A V60 card will have faster transfer speeds to a computer. That’s a big time savings for thousands of photos or hours of video footage.

Sony A9 II Lens Recommendations

Sony A9 II SD Card Compatibility

The Sony A9 II is compatible with the SD, SDHC, and SDXC standards.

Each of those standards have different storage capacities and file systems.

Check to make sure the camera has the latest firmware.

The newest SDUC (Secure Digital Ultra Capacity) cards will not work with the A9 II.

SD (Secure Digital) - 128MB to 2GB. (FAT12/16)
SDHC (Secure Digital High Capacity) - 4GB to 32GB. (FAT32)
SDXC (Secure Digital eXtended Capacity) - 64GB to 2TB. (exFAT)
SDUC (Secure Digital Ultra Capacity) - 4TB to 128TB. (exFAT)

Ultra High Speed (UHS)

The Ultra High Speed bus (UHS) is available with SDHC, SDXC, and SDUC memory cards.

There are three different specifications that go up by maximum transfer speed.

Both card slots on the A9 II are compatible with UHS-II. For 4k video or shooting at 20 fps, UHS-II cards are needed because they can write data faster.

UHS ratings are shown on a card label as a Roman number I, II, or III. Product listing will prominently display the rating.

UHS-I - Maximum transfer rate of 104 MB/s
UHS-II - Maximum transfer rate of 312 MB/s
UHS-III - Maximum transfer rate of 624 MB/s

Card Speed Class

Video rating is based off of sustained write speed. If a card can’t keep up with video stream that needs to be written, the recording will abruptly end.

Video rating is shown as a V followed by a number. That’s the sustained write speed the card is rated for.

V30 - 30MB/s - 4k30 video
V60 - 60MB/s - 4k60 video or higher resolutions
V90 - 90MB/s - 8k video or high frame rate video

Speed class is was the first rating system. It is shown as a number inside a “C” on the label.

Class 10 card are likely much faster than 10MB/s. That’s why there are additional ratings for high resolution video.

Class 2 - 2MB/s
Class 4 - 4MB/s
Class 6 - 6MB/s
Class 8 - 8MB/s
Class 10 - 10MB/s or faster

Image Capacity

Here’s the approximate image capacity for high-quality JPEGs from the 24.2 megapixel sensor:

32GB - 4,240
64GB - 8,480
128GB - 16,960
256GB - 33,920
256GB - 67,840

Dual Card Slots

Do Both Memory Card Slots Need to be Used?

No, the Sony A9 II will work with a card in only one slot.

Using both card slots enables the following options:

Mirror the Cards. Both memory cards will have the same files written to them.
Overflow. Once the first card is full, files will be written to the second card.
RAW+JPEG. Raw files will be written to one card and JPEGs of the same images will be written to the second card.

Do SD cards need to match?

No, the SD cards do not need to be the same. They do not need to be made by the same manufacturer. Cards can be different capacities.

Having matching cards helps to prevent compatibility problems from one card being too slow.

Recommended SD Cards

A UHS-II V60 SD card will have the best price to performance. It’ll be much faster than what’s needed to record 4k video, which means transferring video will be faster.

That makes a huge difference when a memory card is nearly full. The difference can be hours, which is why it also makes sense to use a UHS-II card reader.

256GB cards are the smallest capacity I would recommend.

128GB cards can make sense as a JPEG overflow card. That way a 512GB card could be used for RAWs vs having two 256GB cards.

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