Ok so I have been hanging around these forums for a while but I still feel like a bit of a beginner when it comes to the realy technical stuff tbh. Ngl I think you should consider a DIY kit approach rather than just one expensive lens if you want to stay under budget and keep things light. Instead of paying full price for professional new glass, I always try to do the research myself and buy used to save money for the actual travel. Here are some options that might work well for your Europe trip:

• Sony FE 24-105mm f/4 G OSS
• This is basically the classic choice for a reason. That extra reach to 105mm is realy nice for grabbing shots of cathedral towers or far away street scenes without needing to walk closer. It is a bit older now but still works great on the a7 III.
• Sigma 28-70mm f/2.8 DG DN Contemporary
• This one is super light. It is much smaller than the Sony GM versions so your neck wont hurt after walking 10 miles in Rome. It basically gives you that pro look without the pro weight.
• Sony FE 40mm f/2.5 G
• If you want to do some street photography at night without looking like a tourist with a huge camera, this tiny lens is perfect. Iirc you can find these used for way under your $1500 budget. Is it wierd to suggest buying a few things instead of just one? I just think having a setup you put together yourself is more fun. Just make sure to check the glass for scratches yourself if you go the used route!

Sony FE 20-70mm f/4 G Lens.

Saved for later, ty!

Depends on your travel style honestly. If you're doing more street photography and want to stay compact, the Sony FE 35mm f/1.8 is fantastic. Super sharp, great in low light, and you'll barely notice it's there. I did a whole trip through Southeast Asia with just that lens and loved the creative constraint it gave me.

But honestly, I respectfully disagree with sticking only to first-party glass if youre trying to maximize your $1500 budget. Looking at current market analysis, the gap between Sony and third-party manufacturers like Tamron and Sigma has basically closed, especially for the a7 III's 24MP sensor. If you want a one-lens-to-rule-them-all approach for Europe, the Tamron 28-200mm f/2.8-5.6 Di III RXD is technically the most efficient choice for travel. Starting at f/2.8 on the wide end is a massive advantage for architecture and street shots, and the weight-to-focal-range ratio is unbeatable. If you prefer a constant aperture tho, the Tamron 28-75mm f/2.8 Di III VXD G2 is a much better value than the GM. It uses a VXD linear motor that is incredibly snappy for street photography, and you'll save nearly $700 compared to the Sony equivalent. Tbh, spending the full budget on one lens when you can get 95% of the performance for half the price doesnt make sense from a technical standpoint. Save that extra cash for the actual trip and better meals in Italy.

I actually travel with the Sony 24-70mm f/2.8 GM II. Yes, it's expensive and somewhat heavy, but the image quality is absolutely worth it if photography is a serious part of your travel experience. The focusing speed is phenomenal for quick street shots, and the build quality has survived everything from desert sandstorms to tropical humidity.

Yep, this is the way