I stumbled upon this thread after doing some cleanup in my own kit yesterday. Coming from the 5D line, you're going to love the sensor on that new body, but please be careful with the mount integrity. I once had a heavy lens shift slightly on a loose adapter, and I learned the hard way that you should always double-check those locking pins before heading out into the field. I personally rely on the Canon RF 70-200mm f/4L IS USM for my portrait and light travel work—it's incredibly compact, which keeps the strain off the mount. For wildlife, I’ve been using the Canon RF 800mm f/11 IS STM with great success, though I always make sure to keep the firmware updated to avoid any stabilization glitches. Just be methodical with your gear maintenance; if you aren't comfortable cleaning the sensor or checking the contacts yourself, I'd recommend getting it professionally done.

I moved from a 5D to an R6 and honestly, stop burning cash on new RF glass if you don't have to. I bought the Canon Mount Adapter EF-EOS R for $100 used, which saved me a ton compared to rebuying my kit. I serviced my own EF lenses and they perform perfectly on the new body. Here is how I spent my $3k budget wisely: 1. Stick with your EF glass for now. I use my Canon EF 70-200mm f/2.8L IS II USM for wildlife and portraits. It is built like a tank, costs a fraction of the RF version, and the adapter doesn't degrade the optics at all. I did a DIY fix on the stabilizer switch for $15 in parts; the dealer wanted $400 for that repair.

• For your run-and-gun needs, look for a used Canon EF 24-70mm f/2.8L II USM. You can find these for around $1,200 now. It is sharper than the f/4 RF zooms and holds its value better over a 5-year ownership period.
• If you really want a prime, the Canon RF 85mm f/2 Macro IS STM is the best value in the system. It is sharp, cheap, and the macro capability adds utility for studio product shots. Total cost for this setup is well under $2k, leaving you plenty for batteries and memory cards. Don't overpay for the "RF" label when the EF mount is still king for value.

Listen, I’ve been wrenching on engines for 25 years and you don’t replace a perfectly good piston just because a new block came out. Like someone mentioned, keep the EF glass. I picked up a used Canon EF 100-400mm f/4.5-5.6L IS II USM for my wildlife work and it’s sharper than half the new RF stuff. Don't waste your budget on new labels. Buy used, maintain your gear, and stop overthinking the mount. Just get the adapter.

@Reply #1 - good point! I agree that the R-system is a massive jump from the 5D series, especially in terms of autofocus speed. If you want to keep your bag light, just look into some high-quality glass from Sigma or Tamron. You can't go wrong with any modern third-party prime or zoom lens from those brands; they provide incredible sharpness that rivals native glass without the weight or the price tag. I have tested several options from them, and the color rendition is surprisingly close to what you are used to. For your wildlife and studio needs, just stick with any reputable manufacturer's stabilized zoom range. Don't stress too much about the native versus adapted debate. Any professional-grade zoom from those third-party makers will perform perfectly on your new body. Bottom line is, prioritize weight and aperture over the badge.

Been thinking about your question for a few hours now, and honestly... before anyone starts throwing specific focal lengths at you, we kinda need to know what your tolerance is for carrying gear on those wildlife trips. Like, are we talking hiking miles into the backcountry or just shooting from a car window? Makes a massive difference.

• How heavy is too heavy for your actual bag?
• Are you realistically going to swap primes in the field?
• Does stabilization matter more to you than raw low-light aperture? I've been through three of these camera generations and honestly, most people buy the wrong glass first because they skip these details. Figure out your physical limits on weight first, then look at some fast zooms from the major third-party players or stick to basic lightweight manufacturer glass. Things may have changed since the old 5D days, but physics still wins...

Ngl, the Sigma 35mm f/1.4 DG HSM Art and Tamron 35-150mm f/2-2.8 Di III VXD are insane value. Also, I just started learning to bake sourdough bread, it is surprisingly hard. Anyway.

Oh man, welcome to the R-system! Honestly, the Canon RF 24-105mm f/4L IS USM is solid, but if you want that "wow" factor, consider this instead:

• Canon RF 24-70mm f/2.8L IS USM for that dreamy studio look.
• Canon RF 100-500mm f/4.5-7.1L IS USM for wildlife—it's insanely sharp. Keep your EF glass with the adapter; it works flawlessly. Anyway, just grab the 24-70mm and never look back!

To add to the point above: idk, I kinda disagree on just grabbing any third-party glass. I spent all last week researching this and honestly, the native stuff just feels tighter with the AF on these new bodies.

• If you want sharpness, just stick to Canon primes for portraits.
• For wildlife, look at any variable zoom from the big manufacturers.
• Keep the adapter for your old EF glass... it works fine for now.