> the f2.8 on the Tamron actually worth the extra weight when walking 10 miles a day? In my experience, people really underestimate how much that f/2.8 matters on an APS-C body like the Sony a6700. Since youre working with a smaller sensor than full frame, you want to keep your ISO as low as possible to avoid grain when you hit those dim Italian cathedrals. Over the years, I've run the math on this dozens of times... jumping from f/5.6 on the long end of that Sony E 18-135mm f/3.5-5.6 OSS to a constant f/2.8 gives you two full stops of light. Basically, thats the difference between a clean shot at ISO 800 and a noisy mess at ISO 3200. I've tried many travel combos and while the Tamron 17-70mm f/2.8 Di III-A VC RXD is technically superior, its a total brick. If you're budget-conscious and want to save cash for more gelato, look for a used Sigma 18-50mm f/2.8 DC DN Contemporary. Ive seen them going for under $500 lately on some forums. It doesn't have built-in optical stabilization, but your a6700 has IBIS so it doesnt even matter for stills. Another technical sleeper if you want a deal is the Sony Vario-Tessar T* E 16-70mm f/4 ZA OSS. It used to be way overpriced at $1k, but you can snag them used for like $350 now. Its a constant f/4, which is a solid middle ground. Honestly tho, I'd just get the Sigma and crop in. The 26MP sensor on the a6700 lets you crop a 50mm shot to look like 75mm and it still looks sharp. Keep the weight down and the money in your pocket.

I spent two weeks trekking through Portugal last year and went through this exact lens crisis. I started with a heavier setup but ended up switching to the Sigma 18-50mm f2.8 DC DN Contemporary for the weight savings. Honestly, its so light you barely notice it on the Sony a6700 body. When I had the Tamron 17-70mm f2.8 Di III-A VC RXD, it felt like I was carrying a full-frame setup which kinda defeated the purpose of a compact camera for me. The Tamron is stabilized which is nice, but your a6700 has IBIS anyway so its not as essential as it used to be. The trade-off is obviously that 50mm long end. There were definitely times in Sintra where I wished I had the reach of the Sony E 18-135mm f3.5-5.6 OSS to grab architectural details on the palaces. But the Sigma being f2.8 meant I could keep shooting as the sun went down without my ISO hitting 12800. If you're doing 10 miles a day in Italy, that weight difference between the Sigma and the Tamron is gonna feel massive by 4pm. I usually just used the Clear Image Zoom on the camera to get a bit closer when I needed it... it works surprisingly well for social media stuff. Its all about what you value more, the extra reach or not having a sore neck by dinner time.

I was in your exact shoes last summer before a trip to Greece. I ended up grabbing a used Sony E 18-135mm f/3.5-5.6 OSS for about 350 bucks and honestly, i couldnt be happier with how it performed. While that Tamron 17-70mm f/2.8 Di III-A VC RXD is a beast for low light, lugging it around for 12 hours a day is a workout your neck just doesnt need. Heres why I think the Sony is the move for your budget:

• The range is just unbeatable for travel. I used the 135mm end constantly for architectural details on old cathedrals.
• Its super light and balances on the a6700 perfectly without feeling front-heavy.
• Youll save enough cash buying used to basically pay for half your meals in Italy. I know people worry about the slower aperture inside but the a6700 handles high ISO so well that it really didnt bother me. Its a very satisfying setup tho... if you find a good deal, just jump on it.