Why You Don’t Need CFexpress for Videos on Sony A7S3 or A7IV

Have you ever wondered if a CF Express cards is needed for a Sony A7S3 or A7 Mark IV camera?

Many video content creators may be hesitant to purchase a new camera because of the expensive media required, but fear not!

Note: this is important to know, that this post is for film makers and not photographers – if you shoot rapid-burst fire RAW with A7IV a SD card might not be able to keep up.

I’ll teach you how to navigate the media card market in just a few minutes.

CF Express cards can be really expensive, like with prices reaching close to $400 for a 160 gigabyte card.

But, what if I told you they are not necessary at all! – especially if you’re shooting video.

Sony CEA-G160T 160GB compact flash card CFexpress Type A Memory Card (CEAG160T)
  • Write speeds up to 700MB/s and read speeds up to 800MB/s
  • New heat sink design maximizes heat disspiation, allowing long recording times even at 4K/120p
  • Up to 5X more drop impact resistance, and up to 10X more resistant to bending

Last update on 2024-04-19 / Affiliate links / Images from Amazon Product Advertising API

One mistake that many video makers make is confusing the data numbers on this chart.

FormatColor SpaceFramesMax Bitrate (Mbps)
XAVC HS 4K (3840 x 2160)4:2:0, 10bit, NTSC60p150
4:2:0, 10bit, PAL50p150
4:2:2, 10bit, NTSC60p200
4:2:2, 10bit, PAL50p200
XAVC S-I 4K (3840 x 2160)4:2:2, 10bit, NTSC60p600
4:2:2, 10bit, PAL50p500
XAVC S-I HD (1920 x 1080)4:2:2, 10bit, NTSC60p222
4:2:2, 10bit, PAL50p185

If you take look at the specifications for the A7 Mark IV camera, you can see that the highest data rate for video is 600Mbps.

However, it’s important to remember that this is measured in megabits per second, not megabytes per second.

To calculate how many megabytes per second you need, you must divide this number by eight.

In this case, 600Mbps divided by 8 is only 75 megabytes per second.

This is where SD cards come into the picture

SD cards are divided into “video class numbers,” such as V10, V30, V60, or V90. If your SD card doesn’t have a video class number, it’s likely too slow for recording high-quality video.

  • A V30 card, for example, is rated to sustain a write speed of 30 megabytes per second.
  • A V60 card is rated to sustain 60 megabytes per second
  • A V90 card is rated to sustain 90 megabytes per second.

Going back to the A7 Mark IV camera, we can see that the highest data rate is 75 megabytes per second.

This means that a V90 SD card will be able to handle all the data rates coming out of this camera, and you will never need a CF Express card.

However, if you are not recording the highest quality video, you may be able to get by with a V30 card. – i dont recommend a v30 card, i’d be going for a V60 card at a minimum.

Lexar 128GB Professional 1667x SDXC Memory Card, UHS-II, C10, U3, V60, Full-HD & 4K Video, Up To 250MB/s Read, for Professional Photographer, Videographer, Enthusiast (LSD128CBNA1667)
  • Get high-speed performance with UHS-II technology (U3) for a read transfer speed up to 250MB/s (1667x)
  • Captures high-quality images and extended lengths of stunning 1080P full-HD, 3D, and 4K video with a DSLR camera, HD...
  • Large capacity options up to 256 GB let you enjoy shooting longer without changing cards

Last update on 2024-04-19 / Affiliate links / Images from Amazon Product Advertising API

These can be found on Amazon or other local stores for as low as $50, compared to a CF Express card which can cost up to $390.

It’s important to pay attention to the data rates and video class numbers when choosing a media card for your camera.

By understanding these numbers, you can save hundreds or even thousands of dollars by choosing the right SD card instead of a CF Express card.

The V90 SD Cards i own personally.

I just bought of myself I just bought two of these Kingston canvas react plus UHS-II cards. they are able to do 90 megabytes per second sustained,

but you almost only need to know that some cards are more reliable than others and you need to see what people are saying about the cards.

I like kingston, they are of my favorite brands, and they have never failed me so I’m going to buy Kingston

Kingston Canvas React Plus 128GB SD Card | SDXC UHS-II | 300R/260W U3 V90 | Full HD/4K/8K | SDR2/128GB
  • Ultimate speeds to support professional camera use
  • Capture 4K/8K Ultra-HD high-speed shots without dropping frames
  • Top-of-the-line performance for professional content creators

Last update on 2024-04-19 / Affiliate links / Images from Amazon Product Advertising API

Why its not good enough

If you are shooting for images and photography – a V90 can handle a lot.

But just not if you are shooting uncompressed raw or even compressed raw AND you are shooting multiple images per second.

The image files are about 33 Megabyte – and the maksimum speed is 10 images per second, which is 333 Megabytes per second.

But many have tested V90 cards to get up to 6 and at the lowest 3 images per second.

So its only if 3 – 6 images per second is not fast enough for you!

My name is Simon, and this is my website. I maainly talk about camera gear, but also other stuff i own.

This website is an extension of my YouTube channel called: Simon's Danglish Reviews.

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