Best Memory Cards Compared In-Camera | Sony A7III

The Sony A7 III, like the A9 and A7r III, has some very impressive new internal hardware that allows for faster memory card performance, a larger buffer, as well as UHS-II memory card compatibility.

We finally have the full test for the A7 III up and the memory card speeds are very similar to the Sony A7rIII and the Sony A9, slightly faster actually, although the Sony A7 III does have a much smaller buffer.

Best Accessories For The Sony A7 III

Every Lens For The Sony A7III

Best Memory Cards Sony A7III

Configuring your memory card setup for the Sony A7III can be a little confusing and it can be very easy to unnecessarily waste money here if you don’t know what you’re doing. So here are a few useful tips to help you decide which memory cards to get for your Sony A7 III.

The Sony A7III features dual memory card slots, but only one of those slots is UHS-II compatible.  The second slot is only UHS-I.

If you require always shooting a RAW backup, then there is no point in using UHS-II memory cards in either slot, because slot-II, which is UHS-I will slow down performance to that level. That right there should save you a lot of money if you have to shoot RAW backup because you’ll only need to buy UHS-I cards. 

You can shoot RAW with JPG as your backup and your UHS-II speeds will still perform quickly, although expect to lose about 20MB/s in buffer clearing speeds when shooting RAW+JPG because of the extra processing time to write the JPG files.

For Video, UHS-I memory cards are fine so long as they have a U3 rating. The Sony A7III only shoots 4k video at 100Mbps, which translates to 12MB/s. Most UHS-I cards can perform at these speeds, but the camera will require you to at least use a U3 memory card. It will not allow you to use a U1 card with 4k video because it requires the 30MB/s minimum write speed that U3 cards have.

Best SD Cards for Sony A7III & Recommendations

For shootings running a single memory card setup and want the maximum speed, UHS-II V90 cards are the way to go. The Sony A7III has pretty quick performance as long as you’re not using the second UHS-I memory card slot.

V60 UHS-II cards are a great compromise for speed and performance. They still run quick, but cost a lot less.

For hybrid shooters that require video and stills that don’t need backup, a good way to save money is to shoot UHS-II in slot 1, using v90 or v60 depending on speed requirements, then use a UHS-I or UHS-I designed card like the Sony E card in slot two.

Here are some great recommendations only listing the fastest v90 and v60 UHS-II cards with in-camera performance along with the USB-C read and write speeds.

*Rated speed, untested. While the Sony E card is a UHS-II card, its write speed is rated for UHS-I but its read speed is still UHS-II. This makes it the best card for video because it still comes in at a cheap price compared to UHS-II cards, but you still get UHS-II read performance when offloading data.

If I were buying cards today I personally would go Sony G Tough or Sony M Tough in Slot 1, and Sony E in slot 2. But I rarely shoot with backup. I keep slot 2 as overflow or for video. Today in my A7rIII I’m running Delkin V90 and V60 cards and they are also working great.

In-Camera Speed Test

This chart displays how each memory card performs in-camera.

For the tests, we shoot a continuous burst use uncompressed RAW at ISO 100 with a shutter speed of 1/100.

We also test each card to check for 4k recording compatibility. Sony cameras don’t like some cards. For example, many Samsung cards even though they are U3 and SDXC, get rejected by the camera with an error that they are not U3 cards.

The USB read and write speeds are taken from USB-3.0 readers which are different from the USB-C reader that I used for the numbers above.

Sony A7III Camera Specs Buffer Questions

Sensor: 24MP Full-Frame Exmor R BSI CMOS Sensor
Processor: BIONZ X Image Processor & Front-End LSI
What Size Is The Buffer? 1.5GB estimated
What Memory Cards are Compatible? UHS-I / UHS-II
How Long To Clear Buffer? 9:36
How Many Uncompressed Shots To Fill Buffer? 46

Sony A7 III – Amazon / Adorama / BHphoto

UHS-II vs. UHS-I Memory Cards In The Sony A7rIII

While the Sony A7 III takes advantage of UHS-II memory cards, speeds will be bottlenecked to the slowest memory card in the camera depending on how you’re using slot 1 and slot 2 with the recording modes.

Recording Mode Standard | Slot 1 | Auto Switch On

If you’re using Slot 2 as an overflow, then you will get UHS-II memory card speeds in Slot 1 until the card fills up. Then once the camera switches to Slot 2, speeds will slow down to the speed of the card in Slot 2 and that slot will only be able to produce UHS-I speeds.

On my Sony A7rIII Auto Switch was turned off by default, so you will need to enable this yourself to gain this benefit.

Record Mode Simult. RAW+RAW

If you’re shooting Slot 1 and Slot 2 as a backup, then memory card write speeds will be throttled to the slowest card. If you shoot like this often, you may not see any benefit to using UHS-II cards.

Record Mode Simult. RAW+JPEG

We no longer test RAW+JPEG, but since JPEG files are smaller, you don’t see the same bottleneck as when you’re backing up with RAW to slot 2.

However, shooting RAW+JPEG does slow down the performance of the buffer significantly as it requires more processing as the cards are written to and this task is usually is not multithreaded.

Shooting Uncompressed RAW will make massive files and you will fill your buffer a lot quicker, but they won’t slow down your memory card write speeds.

Best Memory Cards 4k Video Sony A7 III

Shooting 4k video with Sony cameras does require some minimum specs for it to work.

Aside from some cards just not working (like Samsung), you will need a U3 memory card to shoot 4k video with the Sony A7 III.

Sony upgraded its firmware in 2016 so that you can now use SDHC memory cards for 4k video, however, you still need to use U3 memory cards. Here is a break down of some memory card stats and what all the numbers mean.

Class 10 / U1 – NO 4k!

Class 10 and U1 are one and the same. It has to do with minimum write speeds a card is capable of. A Class 10 or U1 card should be able to sustain 10MB/s write speeds in any situation, sequential or random.

However, 4k will not work here.

U3 – 4k compatible

U3 is the minimum requirement for 4k video. It has a minimum performance speed of 30MB/s. So under any circumstance, it will be able to keep up with the 4k video bitrate demands regardless of whether the card is fragmented or not.

V30 – 4k compatible

V is the newest rating system. It also has to do with minimum write speeds. V30 is the same as U3, 30MB/s. It will also work for 4k video. Typically if a card is V30 it’s also U3 and meets Sony’s requirements.

V60 – 4k compatible

Even faster than V30 is V60. 60MB/s guaranteed minimum write speeds. The thing is with the V60 and V90, although the cards can perform with the guaranteed write speed of 60MB/s it doesn’t mean the camera can. Usually, a memory card’s performance is limited by the camera’s capabilities.

V90 – 4k compatible

Like V60 this means minimum speeds of 90MB/s. You mostly only see this on UHS-II cards.

What Size Memory Card Do You Need?

I put together a nice guide based on specs and my experience to help you decide which size memory card to buy.

For Stills

I still recommend 64GB.

For photographers shooting only still I recommend buying a 64GB card. While I never use more than 64GB in a day of shooting, occasionally I’ll forget to clear off my camera before going out to shoot again and having the extra memory is nice.

Also, if you decide to record video, the 64GB cards will allow you to record without breaking the video files up into 4GB chunks since 32GB cards can only be formatted with a 32-bit filesystem.

For Video

The memory card size for the Sony A7III when recording video depends on what format you are recording and how you plan on using the camera.

There are a few details you should note. Take a look at the max bitrates.

4k 24p / 30p Max Bitrate: 100Mbps

1080 24p / 25p / 30p / 50p / 60p Max Bitrate: 50Mbps

To get the maximum quality or 100Mbps at 24fps or 30fps with the Sony A7III you will need to record in 4k unless you want  100fps or 120fps then you can record 1080p with 100Mbps.

If you only want 1080p 24fps or 1080p 30fps, you will only get half the bitrate of 50Mbps. So even if you need 1080p, it’s better to record 4k then scale down, which if done correctly in a 16-bit sequence will results in a 4:2:2 data compression. That’s the theory anyway.

Maximum Video Record Times by Memory Card Size

Here is a handy chart you can use to find the best size memory card you’ll need for your recording format. Or how many minutes you can get with the different formats on with different size cards.

For video shooters, filmmakers, I recommend 128GB cards and I highly recommend you clear off your cards regularly for backup throughout the shoot when on a paid production.

How To Avoid Counterfeit Cards

Unfortunately, counterfeit cards are still a problem and they pop up from time to time at different retailers. 

The best way to avoid counterfeit cards is to avoid buying cards off auction sites. Instead, always buy cards from trusted sources.

If a memory card is counterfeit, usually it has a hacked controller which will tell you the card is bigger than it really. For example, you buy a 128GB card, you then put the card in your camera and it tells you it’s 128GB, but there is only actually 32GB of flash memory. You might shoot for months or weeks before breaking past 32GB, and when you do, the card will fail.

This is why so many people have memory card failures these days, they’re actually just using counterfeit cards without knowing it.

How to check if your card is counterfeit?

Easy, whenever you buy a new card, always max its capacity. It should get very close to the rated capacity without any issues.

You can do this by copying files from your computer, or by recording video. This will be a little difficult with a 30-minute record limit, so I recommend just copying files if you can.

You could also run a continuous burst, but if you decide to do that make sure to put your camera into electronic shutter mode so you don’t wear out your shutter.

Best Memory Cards Sony A7 III | Bottom Line

Going with the Sony G or Sony G Tough cards is your bet, but other cards have been working well for us, such as Delkin, Transcend and Toshiba.

When using UHS-I cards, stick with U3 so that you can still record video and avoid Samsung and you’ll likely be free of any problems.