If you curious about which are the best memory cards to use in the Sony a7S III then this article should help solve that curiosity.

Sony a7S III Forum & Facebook Group
If you are looking for further help and advice on the a7S III or would simply like to share your photos and videos, then please head over to our friendly Sony a7S III Forum. If you prefer Facebook then I also run the Sony a7S III Shooters Group and the Sony Alpha Video Shooters Group.
Before we get started it’s important to know that the a7S III features two media card slots and both of these slots are compatible with the new CFexpress Type A cards as well as SDXC/SDHC cards supporting UHS-I and UHS-II speed classes.
Sony a7S III Memory Cards (Contents)
- CFExpress Type-A Memory Cards
- Top 10 UHS-II Memory Cards
- Top 5 UHS-I Memory Cards
- Which Memory Cards are Supported?
- What Size Memory Card Do You Need?
- UHS-II + CFexpress Memory Card Readers
CFExpress Type-A Memory Cards
The Sony a7S III is the first Alpha camera to support the new CFExpress Type-A Memory Cards and currently Sony is the only manufacturer supplying these cards so your choices are rather limited for now I’m afraid.
1. CEA-G CFExpress Type-A (800/700)

The CFexpress Type A cards are ideally suited for high-speed continuous shooting of more than 1,000 uncompressed RAW still images, as well as 4K 120p movie recording at high bit rates with the Slow & Quick Motion function when paired with new Alpha 7S III. These cards can write up to 700MB/s and read up to 800MB/s and currently there are 80GB and 160GB versions available.
Top 10 UHS-II Memory Cards
Here are my top 10 recommendations for UHS-II sd cards for the a7S III:
1. Sony SF-G Tough UHS-II (300/299)

The Sony SF-G Tough cards are rated v90 for video and have a read speed of 300MB/s and a write speed of 299MB/s.
Tough memory cards are 18 times stronger than standard SD cards, bend proof to 180N, drop-proof to 5 meters, waterproof to a depth of 5 meters for up to 72 hours (IPX8 rating) and dustproof with an IP6X rating. The cards feature a one-piece ribless structure and don’t have the common lock switch, they are also X-ray proof, magnet proof, anti-static and temperature proof.
I have several of these cards and they are definitely fast and so far touch wood I haven’t had any issues with them.
2. Lexar Professional 2000X UHS-II (300/260)

The Lexar Professional 2000X cards are rated V90 for video and have a claimed read speed of 300MB/s and a write speed of 260MB/s.
3. ProGrade V90 UHS-II (300/250)

The ProGrade V90 cards are rated V90 for video and have a claimed read speed of 300MB/s and a write speed of 250MB/s.
4. Transcend SD 700S UHS-II (285/180)

The Transcend SD 700S cards are rated V90 for video and have a claimed read speed of 285MB/s and a write speed of 180MB/s.
5. Manfrotto Pro Rugged UHS-II (280/250)

The Manfrotto Pro Rugged cards are rated V90 for video and have a claimed read speed of 280MB/s and a write speed of 250MB/s.
Price Check & Buyer Reviews for Manfrotto Professional UHS-II
At: Manfrotto
6. Sony SF-M Tough UHS-II (277/150)

Sony’s SF-M Tough Series are similar to the more expensive SF-G version but these are only rated V60 for video and their read time has been cut to 277MB/s and the write time to 150MB/s.
7. Sony SF-M UHS-II (277/150)

Sony’s SF-M Series are identical to the SF-M Tough Series just without the added toughness so they cost a little less. The Sony SF-M cards are rated V60 for video and have a claimed read speed of 277MB/s and a write speed of 150MB/s.
8. ProGrade V60 UHS-II (250/130)

The ProGrade V60 cards are rated V60 for video and have a claimed read speed of 250MB/s and a write speed of 130MB/s.
9. SanDisk Extreme Pro UHS-II (300/260)

The SanDisk Extreme Pro cards are U3 rated (30MB/s) and SanDisk has not given them a V rating, so I don’t recommend them for 4k or 8k video. They have a claimed read speed of 300MB/s and a write speed of 260MB/s. I have quite a few of these cards because they are less expensive than the Sony Tough cards and still perform very well.
10. Sony SF-G UHS-II (300/299)

The Sony SF-G UHS-II memory cards are just as fast as the above Tough version. They are a little cheaper but only if you can find them, as for some reason Sony decided to obsolete them.
The Sony SF-G cards are rated U3 and have a read speed of 300MB/s and a write speed of 299MB/s.
Top 5 UHS-I Memory Cards
As well as UHS-II SD cards the Sony a7S III also supports the slower UHS-I cards. I’ve not had the chance to test these in the a7S III yet but here are my test results from my a7III tests:
1. SanDisk Extreme Pro UHS-I (170/90)

The SanDisk Extreme Pro cards are rated V30 for video and have a claimed read speed of 170MB/s and a write speed of 90MB/s.
2. Sony Professional Series UHS-I (95/90)

The Sony Professional Series cards are rated U3 and have a claimed read speed of 95MB/s and a write speed of 90MB/s.
Price Check & Buyer Reviews for Sony Professional Series UHS-I
At: Amazon
3. SanDisk Extreme UHS-I (150/70)

The SanDisk Extreme cards are rated V30 for video and have a claimed read speed of 150MB/s and a write speed of 70MB/s.
4. Sony Expert Series UHS-I (94/70)

The Sony Expert Series cards are rated U3 for video and have a claimed read speed of 94MB/s and a write speed of 70MB/s.
Price Check & Buyer Reviews for Sony Expert Series UHS-I
At: Amazon
5. Transcend 500S UHS-I (95/60)

The Transcend 500S cards are rated V30 for video and have a claimed read speed of 95MB/s and a write speed of 60MB/s.
Which Memory Cards are Supported?
The Sony a7S III supports SD/SDHC/SDXC UHS-II + UHS-I memory cards in both slots and also CFExpress Type-A cards.
What Size Memory Card Do You Need?
For shooting stills I would recommend a minimum memory card size of 64GB.
For each memory card this will give you around 3500 images if you shoot JPEG (Extra Fine) only, 1750 images when shooting RAW & JPEG (Compressed RAW), 2400 RAW only images (Compressed RAW), 1000 RAW & JPEG images (Uncompressed RAW) and 1200 images shooting uncompressed RAW.
If you are shooting a lot of continuous bursts then you might want to use 128GB cards instead.
For shooting video the size of memory card will depend on the format that you are recording in.
Memory Card Readers
Sony MRW-G2 CFExpress Type-A Card Reader

Optimised for the new CFexpress Type A memory cards, the CFexpress Type A/SD card reader (MRW-G2) provides SuperSpeed USB 10Gbps (USB 3.2 Gen 2) transfer speed, via its USB Type-C® connector, allowing creators to establish an efficient workflow when dealing with high-resolution image files, 4K video and other types of high-volume data. When combined with a CFexpress Type A card, it allows users to transfer data approximately 2.8 times faster than with conventional media. The MRW-G2 card reader can be used with CFexpress Type A and SDXC/SDHC (UHS-I and UHS-II) memory cards.
Sony MRW-S1 UHS-II USB Memory Card Reader/Writer

Sony’s MRW-S1 UHS-II USB SD Card Reader/Writer enables the fast transfer of data via a USB 3.1 interface. It can read/write to UHS-II SD Cards and is backward compatible with UHS-I SD cards. The MRW-S1 together with Sony SF-G cards can transfer files to and from your computer at around 2.6x faster than UHS-I cards. It also works perfectly with other UHS-II cards like the SanDisk Extreme.
I don’t plan on buying the a7S III myself as I don’t shoot enough video to justify the cost. However, I will be renting one as soon as they are available so that I can run a series of memory card tests to provide you with the most reliable and comprehensive information on which are the best memory cards for use with the a7S III.
Thanks for doing this article. I have in A7Siii and I have not been able to use the Sony M card. I’ve contacted B&H and they are asking me to send my camera back in, which is very upsetting, considering that I was one of the first to order and now may have to wait a year to get another one. I have four of those UHS-II cards and none of them will work in the camera. The store is saying that it must be something wrong with the camera and have not tested a copy in store with any UHS-II cards against that Sony card. I cannot just go grab one of the other $200 cards on your list as they are all sold out everywhere. So I guess I have to give up my camera. I was wondering if you can verify that the Sony card (#7 in your first group) will function in a rental copy.
Thanks
Rod
Sorry for the slow reply Rod. I’ve been a little swamped with comments and messages recently but trying to catch up now! It’s strange that your cards are not working at all. Which video settings are you trying to shoot in?
We have the same problem. My Sony M card v60 R:277MB/s is not working on my camera. It’s saying unable to use a memory card but I have another version of the Sony M R:260MB/s which is not a v60 but works perfectly though cannot record any 4k120p. Have B&H resolved the issue with yours?
I ended up getting my camera through another vendor. It is not B & H‘s fault. At the time they did not know the answer to this question. They had me ship the camera back to them, and I guess they ended up sending it back to Sony. But this put me back on a waitlist and it is possible that I would’ve had to wait till next year to get my camera. In the meantime I had put in another order to make sure that I got one and when it came I canceled with B&H. So he has now determined that this is a problem with this particular card. The newest cameras ship with a flyer. It says that if you were having this problem, contact them through there website. When you get to the website there is a number that you have to call. Then you will speak to a person who will collect all your information. But you have to send them the card and you have to be able to find your receipt. I had gotten mine through Amazon, so I had to find a receipt in my Internet notes. Amazon does not do receipts, so I had to print out an invoice. It cost approximately $12 to send my four cards back to Sony, but they quickly got me four more cards that now work. I actually just got them last night. If you do not know the information, you may be able to call B&H to get that email address or phone number to call. I am not sure where I put my flyer.
In the meantime, do not send your camera back. The camera is fine. I have not tested the new cars to see what frame rates they can do and what bit rates. But your original card is considered effective. Hopefully you can find a receipt to return it. I was worried that Sony wouldn’t except my cards since I had gotten them through Amazon. In the meantime also, I had bought two of the smaller 80 GB CF express type a cards. These are ridiculously expensive. However, so are the UHS type two cards that will also work for all of the bit rates and frame rates in this camera. The Prograde and Lexar V90 UHS-2 cards are really all you need. I think they are all you need for almost everything. If you want to find out exactly what they will and won’t do, I think Gerald Undone has a video on it. Also check out some very nice videos on this by Matt “WhoisMatt” Johnson.
So, B & H lost my money because they did not know this at the time. But they have got rich off of me before so it really doesn’t matter to me, laugh out loud.
Cheers