Sigam 18-50mm f/2.8 DC DN C. https://www.bhphotovideo.com/c/search?Ntt=18+50mm+F2+8+DC+Contemporary+Sony&BI=8941&KBID=10361&SID=12345&DFF=d50

For my money, the Tamron 17-70mm f/2.8 Di III-A VC RXD is the ultimate travel lens for Sony APS-C. Constant f/2.8 aperture, excellent image quality, and vibration compensation. Slightly heavier than other options but the low-light performance and image quality make up for it. I've taken mine through Europe and Asia with zero regrets.

^ This. Also, Jeremy is spot on about the weight, but tbh I worry way more about technical quirks. I remember taking a trip to the coast with a setup I thought was perfect, but I ran into some weird communication errors between the lens and my Sony a6000 at the time. It turned into this whole ordeal where:

• The lens would just randomly disconnect if I zoomed too fast
• Metadata kept getting stripped for no reason
• I missed a pod of dolphins because the AF froze up It was super frustrating because I'd spent weeks researching the best specs only for the firmware to act like it didnt know what a Sony body was. My cousin had the same thing happen with his Sony a6400 and some legacy mount adapter later that year. Just goes to show that even if the glass is sharp, if the tech isnt talking right, you're just carrying a very expensive paperweight around. Anyway, just some food for thought...

Tamron 17-70mm f/2.8

For the best travel lens for Sony APS-C cameras, consider these options:

1. Sony 16-55mm f/2.8 G - Great for versatility and low light.
2. Tamron 11-20mm f/2.8 Di III - Excellent for landscapes and architecture.
3. Sony 18-200mm f/3.5-6.3 OSS - A solid all-in-one option for various scenarios.

These lenses offer a good balance of quality and convenience for travel photography.

I've been shooting with these bodies since the NEX days and if there's one thing I've learned, it's that the best lens is the one you actually bother to carry. Years ago, I brought a huge bag of glass on a trip through Italy and ended up with a sore shoulder and missed shots because I was too busy faffing around with gear. I eventually switched to a high-quality constant aperture zoom that stays on my camera 95% of the time. It really changed the game for me. Being able to go from a wide landscape shot to a tight detail without changing lenses means I stay in the moment. The optical performance was good enough that I didnt feel like I was compromising, even in low light. Tbh, the weight savings alone made the experience way more enjoyable. Focus on something that balances size and speed... your back will thank you later.

For a versatile, compact travel lens under $500 for your a6400, consider the Sigma 18-50mm f/2.8 DC DN. It offers a great zoom range, excellent image quality, and is highly portable. Alternatively, some prefer a prime lens like the Sony 35mm f/1.8 OSS for its compact size and low-light performance, though it lacks zoom. Check recent reviews for detailed comparisons.

Sigma 18-50.