Stumbled upon this today and totally get the frustration. Moving to mirrorless is a massive investment, and using that old EF glass with an adapter on a high-res body like the R5 Mark II is basically like putting budget tires on a Ferrari... it just wont feel right. In my experience over the years, if you are already worried about sharpness, the Canon RF 24-70mm f/2.8L IS USM is the only lens that wont leave you wondering what if when you get home. I have tried many setups for international travel, and while the f/4 version is definitely lighter, you are gonna miss that extra stop of light the second you step into a dimly lit church or hit a narrow street at dusk. Italy is all about those moody interiors and evening walks, so that 2.8 aperture is a lifesaver.

• Low light performance is significantly better for those indoor shots you mentioned.
• The bokeh and subject separation look much cleaner on a 45mp sensor.
• The image stabilization paired with your R5 body is basically magic for handheld video.
• Weather sealing is rock solid for peace of mind if you get caught in a spring shower. It is a bit beefy, but honestly, just grab a solid strap like the Peak Design Slide to distribute the weight across your shoulder. Spending $2399 is a lot, but its better than spending half that on the f/4 and regretting it halfway through your trip because your indoor shots look mushy. Let me know if you want to know more about the weight stuff, I can compare a few others for you.

Honestly, if you want that 45mp sensor to actually shine, stop looking at the f/4 version. In my experience, the Canon RF 24-70mm f/2.8L IS USM is the only way to go if you need speed for those dim Italian cathedrals. Its kinda heavy, but the sharpness is on another level. I've tried many zooms over the years and this one stays on the camera. Just get it and dont look back.

Just catching up on this thread and honestly, I totally get why youre happy with the R5 Mark II upgrade, its such a beast. Looking at the MTF charts and diffraction limits for that 45mp sensor, it really does demand high-end glass to shine. I am a bit of a nerd for the technical specs tho. Before I weigh in, I am kinda curious about a couple things:

• Are you planning on doing any video while youre over there or just stills?
• How much do you typically crop your photos? Not sure if this helps, but I think I heard somewhere that the weight difference between those zoom options isnt as huge as people make it out to be when you factor in the adapter weight you are already carrying. IIRC, the cheaper version saves a ton of money which is always nice. I am pretty satisfied with my gear but for Italy, those dim interiors might be tricky if you go the slower route... just something to think about.

> is it worth the price hike over the f4 version? Saw this earlier but just now responding... Italy is going to be incredible with that R5II! You're gonna have a blast!! One huge thing to watch out for tho... definitely avoid those sketchy gray market sellers even if the price is lower. For a big trip like this, you need the reliability of a legit warranty. If your AF goes wonky in Rome, you dont want to be stuck with a paperweight! I honestly love using the comparison tools on sites like The-Digital-Picture. It lets you see side-by-side sharpness crops at different apertures, which is a total lifesaver for making these big decisions. Also, please be careful about using cheap filters! A bad UV filter will totally destroy the sharpness of that 45mp sensor and make you think the lens is the problem. Stick to the good stuff or go bare glass. Its gonna be a fantastic setup once you get it sorted!