For your Leica M11-P, UHS-II V90 cards are recommended for optimal performance with RAW files and video. SanDisk Extreme Pro and Sony TOUGH-G series are excellent choices, offering high read/write speeds. While the M11-P has 256GB internal memory, using an SD card provides extended storage and easier file transfers. For dual-card setups, consider writing to both the internal memory and an SD card for redundancy. Avoid slower UHS-I cards if shooting high-resolution RAW or video frequently.

@Reply #2 - good point! While it is true most cards will get the job done, I actually disagree slightly about needing the absolute fastest specs. In my experience, chasing those top-tier speeds is often just spending money for no real gain with how the M11-P handles data. I used to be obsessed with having the fastest possible cards until an expensive one failed on me during a trip last year. It was a total headache. Since then, I have been much more satisfied with a more conservative approach that focuses on reliability. My current setup involves a mid-range card that cost way less than the flagship ones, and honestly, it works well.

• I stick to proven V60 cards instead of the pricey V90s.
• I treat the internal memory as my primary and use the SD for redundancy.
• I always format in-camera every single time I offload photos. I have had no complaints about buffer lag or write times even with the full 60MP files. Save your cash for a nice strap or more lenses... if you want to know more about how I set up the storage partitioning in the menus, I can definitely help with that!

Any UHS-II SD card is OK.