Canon R5 Mark II + 600EX-RT Compatibility - Need Quick Advice!

[lfram]

I'm getting contradictory information online about flash compatibility and need to order soon due to shipping timing constraints.

**My setup:**
- Canon R5 Mark II
- Canon RF 100mm f/2.8L Macro IS USM
- Canon RF 100-500mm f/4.5-7.1L IS USM

**What I want to buy:**
- Canon Speedlite 600EX-RT (used)
- Canon MR-14EX II macro ring flash

**The confusion:**
Some sources say the 600EX-RT works perfectly with R5 Mark II, others say it's "not recommended" or has significant limitations (lost IR AF assist, weather sealing issues requiring AD-E1 adapter, etc.).

**My intended uses:**
- MR-14EX II for macro work with the 100mm lens
- 600EX-RT for wildlife/herp photography with the 100-500mm
- Potentially using both flashes together wirelessly

**Questions:**
1. Do any of you actually use a 600EX-RT with R5 Mark II? Any real-world issues?
2. Does the MR-14EX II work well as a wireless trigger for the 600EX-RT?
3. Should I go with a newer 600EX II-RT instead, or different speedlight entirely?
4. Are the "limitations" I'm reading about actually problematic in practice?

I know the 600EX-RT is older, but the price is right and I've heard good things. Just want to make sure I'm not buying incompatible gear!

Thanks for any real-world experiences you can share - time sensitive due to shipping logistics.

 

[koenkooi]

The lost IR AF assist is true, as far as I can tell no Canon mirrorless body supports that.

 

[lfram]

The lost IR AF assist is true, as far as I can tell no Canon mirrorless body supports that.

Yes, but is it not true that this is not a practical issue since:
the R5 Mark II has excellent low-light autofocus capability; and the camera has its own AF assist beam (LED-based)?

 

[Moritz_RD02]

I've got the very same combination - the 600-EX RTii and the R5m2, that is. Never noticed anything, I've always deactivated the AF assist as it almost always slowed down focussing to a crawl. The weather sealing bit is true, you would need the AD-E1 adaptor to "fully" seal that combination.

Other than that I feel hard pressed to see any real world problems with that combination.

The lost IR AF assist is true, as far as I can tell no Canon mirrorless body supports that.

Never knew that one.