For your situation, the R6 II draws way more power than a 5D III. To hit those 40fps bursts, you basically need the higher voltage. Honestly, V90 cards are overkill; the ProGrade Digital SDXC UHS-II V60 Gold 128GB handles 4K60 perfectly. For weddings, grab a SmallRig L-Bracket for Canon EOS R6 Mark II 4153. It makes tripod swaps sooo much faster... and the Peak Design Slide Camera Strap SLL-BK-3 is a lifesaver for travel!

In my experience, maybe don't go too crazy yet? 1. Grab one Canon LP-E6NH Lithium-Ion Battery ($79) for the high speeds, but ur old ones work fine mostly.
2. Get a Lexar Professional 1667x 128GB SDXC UHS-II Card V60 ($40). V90 is SO expensive, I think V60 is enough for 4K?
3. Definitely get a ULBTER Screen Protector for Canon R6 Mark II ($10). Honestly, save the rest for lenses! gl!

Seconding the recommendation above!! Tbh, I went through the same gear paralysis when I moved over from my DSLR. If you've got $600, you can actually get everything you need without overspending on stuff that doesn't actually matter for travel or weddings. • SD Cards: V60 vs V90
- Pros/Cons: V90 is highkey overkill for 4K60 and costs a fortune. V60 handles the bitrates perfectly.
- Best Choice: SanDisk 128GB Extreme PRO SDXC UHS-II Card V60 • Batteries: Old LP-E6N vs New NH
- Pros/Cons: Your old ones are fine for backups, but they wont hit the 40fps burst. The newer NH style is a must for the 'future' feeling you mentioned.
- Best Choice: SmallRig LP-E6NH USB-C Rechargeable Camera Battery 4084 (super handy cuz you can charge it with a phone cable!) • Support: Standard Plate vs L-Bracket
- Pros/Cons: L-Brackets add a bit of weight but make vertical shots for social media or travel sooo much easier on a tripod.
- Best Choice: SmallRig L-Bracket for Canon EOS R6 Mark II 4153 Honestly, the autofocus on this body is basically magic. Just dont overthink the cards... V60 is plenty!! gl with the new rig 👍

Like someone mentioned, the older power cells do fit, but I'm gonna politely disagree about using them for anything serious. I tried to make my old ones work alongside some cheap third-party options when I first got the camera, but it was honestly a mess. The camera's performance is so much more consistent with the official brand versions. I've been much more satisfied since I swapped them out... the high speed modes actually stay active like they should. I also did a little comparison between the mid-tier cards and the high-end ones from another brand. While the mid-tier ones are okay for travel, I noticed they lagged during fast bursts at a wedding I was helping with. I ended up going with the more expensive ones for the extra speed. It's just safer. I dont really need all those extra brackets and fancy straps people recommend either. My current setup is pretty stripped down and it works well for me without adding too much bulk to my bag.

tl;dr: focus on data redundancy and battery safety over flashy accessories. Adding my two cents here cuz I've seen folks run into issues. Be careful with those old LP-E6N batteries from your 5D III. They might work for casual travel shots but for wedding work, the R6 II is a different beast and you will lose that high speed mechanical shooting mode when the charge drops even slightly. I would suggest checking out the speed tests on Cameratimes or similar gear review sites before buying any more cards; they show exactly which ones actually hit their advertised speeds in this specific body. Also, make sure to set your recording to dual slots (backup mode) immediately for your professional gigs. It sounds obvious but some people forget and it is the biggest risk when moving to mirrorless where firmware can occasionally glitch. I would honestly stay away from cheap third-party batteries for this body too, it just isnt worth the reliability risk when you are shooting a once-in-a-lifetime event.

I honestly had such a headache making the switch from my 5D series. It is pretty disappointing how much extra cash you have to drop just to get the R6 II to perform like the beast it is supposed to be. I really struggled with the battery situation because my old ones just did not cut it for the high speed modes, which felt like a total letdown after years of reliability. It is frustrating to realize that your old kit is basically holding back your brand new body.

• Sony TOUGH-M Series SDXC UHS-II 128GB V60 (around $55). I actually had issues with cheaper cards failing during long 4K sessions, so I had to upgrade to these for the peace of mind. They are way more rugged than the standard plastic ones.
• Kirk Enterprise Solutions L-Bracket for Canon EOS R6 Mark II ($145). I was not as happy as I expected to be with the generic brackets... they never seemed to sit right on the RF bodies and would twist under pressure.
• Satechi 108W USB-C PD Desktop Charger ($75). I was so annoyed to find out my old USB hubs wouldnt actually charge the camera in-bag. You need a high-wattage PD source for that feature to even work. Honestly, I wish the transition was smoother but you basically have to rebuild your kit from the ground up for mirrorless. It is a bit of a money pit tho.

Yep, this is the way