If you want best performance, just get CFexpress Type-A cards, such as Lexar CFexpress Type A Gold Series. And UHS- II V90 cards are also a good choice for a7IV with a cheaper price, such as SanDisk Extreme Pro UHS-II V90.

I bought the Lexar 160GB Professional CFexpress Type A SILVER Series Memory Card. Very fast.

CFexpress Type A vs UHS-II SD Cards

• CFexpress Type A:

  • Pros: Faster read/write speeds (up to 800 MB/s read, 700 MB/s write), ideal for 4K 60p and 10-bit 4:2:2 video, more future-proof.
  • Cons: Higher cost, limited options.

• UHS-II SD Cards:

  • Pros: More affordable, sufficient for most photography and 4K video, wide availability.
  • Cons: Slower speeds (up to 300 MB/s read, 250 MB/s write), may struggle with high-bitrate 4K 60p video.

Recommended Specs

• Speed Class: V90 (Video Speed Class 90).
• Read/Write Speeds:
  • UHS-II: At least 250 MB/s write, 300 MB/s read.
  • CFexpress Type A: 700 MB/s write, 800 MB/s read.
• Durability: Waterproof, shockproof, temperature resistant.

Recommended Models

• CFexpress Type A:

  • Sony TOUGH CFexpress Type A
  • ProGrade Digital CFexpress Type A

• UHS-II SD Cards:

  • Sony TOUGH UHS-II
  • SanDisk Extreme PRO UHS-II
  • ProGrade Digital UHS-II

Slot Usage

• Slot 1: Use for primary storage (CFexpress Type A for max speed).
• Slot 2: Use for backup or overflow.

Backup: Ensures data redundancy. Overflow: Extends storage capacity for long shoots.

The Sony Tough-g CFexpress Type A card I used is very well.

For optimal performance with your Sony a7 IV, especially when shooting 4K 60p and 10-bit 4:2:2 video, investing in CFexpress Type A cards is advisable due to their superior write speeds. High-end UHS-II SD cards can suffice for less demanding tasks but may struggle with high-bitrate video.

To add to the point above: you might want to consider how the camera handles different card brands at the same time. I'm not 100% sure but I think I remember reading that mixing a super fast card in slot 1 with a slower one in slot 2 for backup can sometimes cause the whole system to lag or even glitch out during heavy bursts. Be careful with the heat too. High-bitrate 4K 60p can make the camera pretty warm and I've heard certain cards might trigger the overheat warning sooner than others. It's kinda scary when your gear locks up during a shoot, so make sure to check if people are having issues with card compatibility after the latest firmware updates. Honestly, I would suggest getting two of the exact same cards if you can afford it just to keep everything stable. TL;DR: Consistency between slots might save you from weird lag or compatibility glitches. Dont mix and match speeds if you can help it.

For the Sony a7 IV, I'd recommend the Sony Tough CFexpress Type A cards for Slot 1 if budget allows. They offer blazing 800MB/s read and 700MB/s write speeds which are perfect for 4K video at high bitrates. For Slot 2, a good UHS-II V90 SD card like the ProGrade or SanDisk Extreme PRO will serve you well. The dual slot setup gives you great flexibility - I use CFexpress for video and SD for stills.

CFexpress Type-A card and UHS-II SD card are recommended!