So, congrats on the 5D IV! Honestly, its still such a solid workhorse even with the mirrorless craze. I mean, I've been using mine for years and it's basically a tank. For ur situation, here's what I recommend: - **Memory Cards:** To avoid that buffer bottleneck, u *really* need a fast CF card for ur primary slot. I've been super happy with the SanDisk 128GB Extreme Pro CompactFlash Memory Card 160MB/s. It handles those massive 30MP RAW files like a champ. It costs about $60-70 these days, which is a great value. For the SD slot, grab a SanDisk 128GB Extreme PRO SDXC UHS-I Card 200MB/s. Just a heads up, that SD slot is only UHS-I, so the CF card is definately ur speed king for 4K video.
- **Batteries:** I've tried third-party ones, but they're hit or miss... usually throw errors after a few months. I'd stick with the Canon LP-E6NH Lithium-Ion Battery. Its about $80, but it's the newer version for the R series that is backwards compatible and gives way better life than the old Canon LP-E6N Lithium-Ion Battery Pack when ur using GPS or WiFi.
- **Ergonomics:** For portraits, an L-bracket is a total game changer for switching to vertical on a tripod. I swear by the Kirk Enterprise Solutions L-Bracket for Canon EOS 5D Mark IV. Also, seriously look into the Peak Design Slide Camera Strap. The stock strap is kinda trash for long events, and this one makes the heavy body weight disappear.
- **Protection:** Since u mentioned workflow, definitely get a Vello Screen Protector Ultra for Canon 5D Mark IV. It's tempered glass and has saved my screen from belt buckle scratches like a million times lol. Anyway, gl with the new gear! You're gonna love that sensor... its a huge jump from the 70D. cheers!

^ This. Also, totally agree on that SD slot bottleneck... it is such a buzzkill for technical workflows! Since everyone else suggested the pricey boutique stuff, I will chime in with some budget-friendly gear that actually performs just as well.

• For batteries, dont overpay for the Canon sticker. I love the Wasabi Power LP-E6NH 2-Pack with USB Dual Charger because the cells are rated at 2250mAh, which is amazing for the price. Never had an error code on my 5D IV.
• Instead of those 100 dollar L-brackets, check out the SmallRig L-Bracket for Canon 5D Mark IV 2202. It is super solid aluminum and fits like a glove for way less cash.
• If SanDisk CF cards are too pricey, the Lexar Professional 1066x 128GB CompactFlash is a fantastic alternative. It hits those UDMA 7 speeds easily so you wont lag during burst shooting. Honestly, these save you tons of money without sacrificing the performance of that 30.4MP sensor! Enjoy the new body, its a total beast.

> I’m particularly curious about memory card setups... what are you guys using to handle those massive RAW files and the occasional 4K video without hitting a buffer bottleneck? Before I give advice, congrats on the upgrade! The 5D IV is a legend, but that dual card setup is tricky cuz the SD slot is only UHS-I. Itll actually bottleneck your fast CF card if you arent careful. Are you planning on shooting a lot of 4K, or mostly stills? Also, for events, do u usually write to both slots at once for backup? That info basically changes everything for card choice tho.

ngl I am in the exact same boat as you right now... just picked up a 5D IV and the whole memory card buffer thing is confusing the hell out of me. I've been digging through threads for like three weeks trying to figure out if third party batteries actually work long-term or if they're gonna brick my camera, but the info is so contradictory everywhere. It's honestly super frustrating because I just want to go out and shoot without worrying about the tech failing and I still haven't found a straight answer.