1. Get the SanDisk 128GB Extreme Pro CompactFlash Memory Card for 4K.
2. Skip the grip; carry four Canon LP-E6N Lithium-Ion Battery packs to save ur back during weddings!

TL;DR: Reliability > marketing hype. Always check real-world benchmark databases and prioritize a redundant workflow for weddings. I've been shooting events for a decade and honestly, the 5D IV's 500Mbps 4K stream is a beast that reveals which brands actually have decent controllers and which ones just have good marketing. I remember one shoot where a supposedly 'fast' card from a big-name brand just choked mid-ceremony because of the MJPEG overhead—it was a total nightmare. Now, I basically live on sites like Camera Memory Speed to compare actual sustained write benchmarks rather than just trusting what's on the box. The market for CF is shrinking so you've gotta be cautious about what’s still being manufactured to high standards vs just clearing old stock. In my current setup, I always force the camera to write to both slots simultaneously—even if the UHS-I bus slows things down a bit—because having that instant parity is basically the industry standard for pro work, right? It's all about risk management when you're dealing with someone's big day. Stick to verified benchmarks and youll be fine.

Late to the party but I gotta weigh in on the battery situation. Everyone says go for the official grip or a stack of pricey batteries, but I actually went a different direction when I was starting out. A few years back, I got tired of swapping cells mid-ceremony, so I experimented with a DIY external setup using a high-capacity power bank I already owned and a simple adapter cable. It looked a little mad scientist with the cable running into the battery door, but man, it was a game changer for long days. I eventually streamlined it, but it taught me that you dont always need the official high-priced accessories to get the job done. Sometimes a little bit of creative rigging is way more effective than just throwing money at the problem. I also found that those expensive pro straps are kinda overrated... I ended up making my own out of some climbing rope and some hardware I found, and honestly, it is way more comfortable than anything I ever bought in a camera store. Don't feel like you have to buy the most expensive gear just to look the part.

Nice, didn't know that

Yo, huge congrats on the upgrade!! The 5D IV is such a tank, seriously. So, I’ve been looking into the technical side of the 4K video cuz that MJPEG codec is basically a storage nightmare. It records at like 500Mbps, which is insane! Since the SD slot is only UHS-I (major bummer, I know), it highkey bottlenecks. You really wanna grab something like the Lexar Professional 1066x 256GB CompactFlash Card to ensure you dont get those annoying buffer hangs mid-shoot. Tbh, SD cards are fine for stills, but for 4K video? No way. About the battery... Dual Pixel AF is AMAZING but it eats power for breakfast lol. Instead of just more batteries, have you thought about the Canon BG-E20 Battery Grip? It actually helps balance out heavier L-series glass, which makes it feel way more 'pro' during long wedding days. Plus, having that vertical shutter button is a total lifesaver for portraits. For the screen, definitely get the Vello Screen Protector Ultra for Canon 5D Mark IV—it’s real glass, not a cheap film, so it doesnt mess with the touch sensitivity at all. Oh! And since you’re doing weddings, you MUST check out the BlackRapid Sport Breathe Camera Strap. Neck straps are literally the worst for 8-hour gigs. Also, for lighting, the Canon Speedlite 600EX II-RT is basically the king of reliability. It’s got that weather sealing that matches your body. Basically, focus on the stuff that keeps you shooting without stopping! Good luck, you're gonna love it! 👍

Following this thread

Same here!