Been shooting E-mount for a decade and honestly, weight matters way more than people think after four hours of walking. I used to lug around huge zooms until I realized I was leaving my camera in the hotel because my neck hurt...

• Sony E 18-135mm f/3.5-5.6 OSS: This is the most versatile for Japan. You can go from wide street shots to tight details on temple roofs. Its slow, but the a6700 sensor is good enough that you can push the ISO. Just dont expect blurry backgrounds.
• Sigma 18-50mm f/2.8 DC DN Contemporary: I swapped to this recently. Its tiny. I dont miss the 70mm end as much as I thought I would, you just crop in a bit. The f2.8 is huge for those dimly lit shrines.
• Sony E 16-55mm f/2.8 G: Look for this used. Its the actual gold standard for image quality. No stabilization in the lens, but the a6700 has IBIS so it doesnt matter. Its significantly more compact than that Tamron. Id personally go Sigma for the size alone, but if you really need that reach, the 18-135 is hard to beat for versatility during the day.

I totally get the struggle comparing these specs! If you want to truly maximize that a6700 sensor, you really should go with the Tamron 17-70mm f/2.8 Di III-A VC RXD. It is a technical powerhouse. The constant f/2.8 aperture is a must for low light in Kyoto shrines, and the VC (Vibration Compensation) works in tandem with your cameras IBIS for incredibly sharp shots. While the Sigma 18-50mm f/2.8 DC DN Contemporary is tiny and amazing, you will definitely miss that extra 20mm reach for street photography and compressing those beautiful backgrounds. Technically, the Sony E 18-135mm f/3.5-5.6 OSS has great range, but the slow aperture will force your ISO way too high at night. The Tamron offers superior MTF performance and edge-to-edge sharpness. Its a bit beefy, but the data shows the optics are top-tier. Youll love the output!

@Reply #2 - good point! Carrying a brick around Kyoto is a recipe for disaster. I would suggest the Sigma 18-50mm f/2.8 DC DN Contemporary instead. It is tiny and super light. Be careful about the lack of optical stabilization, but the a6700 has IBIS so it should be fine. You might miss the reach, but honestly? Just use the in-camera crop mode... it saves you so much weight and money.

To add to the point above: unfortunately, trying to find that perfect balance of weight and optics often leads to a massive technical headache. I actually spent a weekend trying to measure the resolving power of different internal elements because I was convinced I could DIY a better housing for my glass to save weight. It was a total disaster and didnt work at all. It honestly reminds me of when my buddy tried to optimize his kit for a Kyoto trip by stripping the rubber grips off his body and lenses to save a few grams. He thought he was being a technical genius. Unfortunately, the solvent he used to clean the residue reacted with the polycarbonate casing and started literally melting the exterior. He spent his entire vacation with sticky hands and a camera that looked like it had been through a house fire. It was a complete ordeal. He was so busy trying to find a hardware store in a foreign country to fix his gear that he missed the best lighting at the shrines entirely. Not as good as expected... basically he spent the whole trip looking at technical diagrams in his hotel instead of actually taking photos.

Saving this whole thread. So much good info here you guys are awesome.

Bump - same question here

Wow ok that changes things. Gonna have to rethink my approach now.

Late to the party but this whole thread is 💯. Glad I found it.