Tamron 28-75mm f/2.8 Di III VXD G2 - best option for Canon EOS R5 Mark II currently.

My experience: Canon RF 24-105mm f/4L IS USM is perfect for Canon EOS R5 Mark II. The image quality is excellent The ergonomic design allows for comfortable handling.

I can warmly recommend Tamron 28-75mm f/2.8 Di III VXD G2 for Canon EOS R5 Mark II. The design is modern and compact The image quality out of the box is very good.

My personal experience: I've tested various lenses, and Tamron 28-75mm f/2.8 Di III VXD G2 was superior in all tests. The image quality remains excellent even in challenging lighting conditions, which is important for professional work. Very good future-proofing through modern technology and reliable performance.

For Canon EOS R5 Mark II I would also consider the aperture. Do you need fast lenses for low light?

Just wanted to say thanks for everyone chiming in. Super helpful discussion.

To add to the point above: I think you might want to consider the weight of your setup before committing to anything heavy. Im still kinda new to this but someone told me that carrying a massive lens all day while traveling is basically a workout you didnt sign up for. Not 100% sure if the lighter, cheaper lenses can really keep up with that R5II sensor tho... it seems like a lot of camera for basic glass. Just be careful with the non-weather sealed options if youre going somewhere humid or dusty. I read somewhere that even a little moisture can mess things up if the lens isnt sealed right. Maybe its just me being paranoid but make sure to check that first. IIRC some of the more budget-friendly stuff skips the rubber gaskets to save money. Just my two cents as a newbie tryin not to break anything!

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Regarding what #11 said about "To add to the point above: I think..." - hes totally spot on about the weight factor. Ive seen so many people buy a high-end body like the R5 Mark II and then get overwhelmed by the sheer bulk of the L-series glass that usually goes with it. But heres the thing I've learned over the years... its a bit of a trap. Back in the day, I tried to cut corners on a trip by bringing a budget zoom instead of my heavy f/2.8 glass. Tbh, it was a disaster. That R5II sensor is a technical marvel but its also incredibly demanding. If you put glass on it that isnt up to par, the sensor will literally outresolve the lens. Youll see soft corners and weird artifacts that you wouldnt notice on a lower-res body. My warning is basically dont let the travel light mantra lead you into buying mediocre glass for a 45-megapixel monster. It is like putting budget tires on a Ferrari... it just doesnt work. If you arent willing to carry the weight of a high-quality lens, you might actually be better off with a smaller sensor system. Just something to keep in mind before you drop thousands on a setup that might not actually deliver the sharpness you're expecting when you finally look at the raw files.