Sony A7 IV – Do You Really Need a CFexpress Card?

The Sony a7 IV adds support for the much faster CFexpress Type-A memory cards in slot one.

However, currently only Sony and Prograde are making CFexpress Type-A cards, so they are ridiculously expensive.

So do you really need to use a CFexpress Type-A card in the Sony a7 IV?

Thankfully not, since the a7 IV also supports UHS-II and UHS-I memory cards in both slot one and slot two.

However, there are two instances when you will need to use a CFexpress Type-A card.

Shooting Video in S&Q Mode & XAVC S-I 4k (2x Slow Motion)

If you want to shoot in S&Q Mode with the file format XAVC S-I 4k, a record frame rate of 25p / 30p and a frame rate of 50fps /60fps (2x slow motion) then you will need a CFexpress Type A card. The a7 IV will not let you record in this specific format with a V90 card.

This is documented in the a7 IV Manual and I’ve also tested it myself.

That said, it’s a little odd because if I select XAVC S-I 4k, a record frame rate of 30p and a frame rate of 60fps (NTSC) then record for 10 seconds I get a 805mb file, so it’s recording at 80.5MB/s which is comfortably within the capabilities of a V90 card. What I’ve also noticed is that the bitrate drops to 250M (PAL) and 300M (NTSC) with these settings, it’s not possible to select 500M/600M.

But despite only recording at 80.5MB/s the a7 IV still insists that you use a CFexpress Type-A card. Maybe Sony just wants to sell more CFexpress Type-A cards? Or perhaps this will change with a future firmware update?

But for now, if you want to record with these specific settings a CFexpress Type-A card will be required I’m afraid.

Burst Shooting with Uncompressed & Compressed RAW Files

If you want to shoot continuous bursts in Hi+ Drive Mode with either uncompressed or compressed RAW files and not hit the buffer then you will require a CFexpress Type-A card.

If you use a slow UHS-II card like the Sony SF-M cards or a UHS-I card then you will also hit the buffer when shooting JPEGs and lossless compressed RAW files.

Please note that when shooting in uncompressed RAW, lossless compressed RAW, uncompressed RAW + JPEG or lossless compressed RAW + JPEG the maximum frames per second is reduced from 10 fps to 6 fps. This is why you will not hit the buffer shooting lossless compressed RAW with a UHS-II card but you will shooting compressed RAW.

Here are my in-camera speed test results using a 64GB Kingston Canvas React Plus UHS-II SDXC Memory Card and shooting to slot one in Hi+ drive mode.

Image Type	Shots Before Hitting Buffer	Time to Clear Buffer (Seconds)
Uncompressed RAW (70.3MB)	26	3.85
Compressed RAW (36.6MB)	67	3.40
Lossless Compressed RAW (40.5MB)	Never hits buffer
JPEG Extra Fine (24MB)	Never hits buffer
Uncompressed RAW (70.3MB) + JPEG Extra Fine (24MB)	17	4.53
Compressed RAW (36.6MB) + JPEG Extra Fine (24MB)	24	4.26
Lossless RAW (40.5MB) + JPEG Extra Fine (24MB)	22	3.05

For the price and performance the Kingston Canvas React Plus UHS-II SDXC are the UHS-II cards that I would recommend for the a7 IV unless you need the toughness of the Sony SF-G cards.

I’ve tested 14 UHS-II cards in the Sony a7 IV, you’ll find all of the results in my Sony a7 IV Memory Card Guide.

Summary

With the crazy price of CFexpress Type-A cards I’d definitely only recommend using them if you really need to.

Thankfully the a7 IV clears the buffer a lot faster than the a7 III does, so if you are shooting a lot of continuous bursts in RAW format you might find that UHS-II cards are still fast enough for your needs.

Sony A7 IV Resources