The Canon T8i now shoots 4k at 120Mbps with a 7fps mechanical shutter, which means you will need to buy the better U3 UHS-I cards to get the most reliable performance. Here is everything you need to know about memory cards for the Canon T8i. Use this guide to find the best memory cards for your style of shooting.
Each memory card was tested in the Sony A9II to see which had the best performance. Turns out, there are only four you should buy. I've also included a record length chart so you can see how much 4k video you can get on each card size to help you determine if you need massive cards or not. Use this guide to find the best memory cards for your Sony A9II.