Quick reply while I have a sec, but honestly, I gotta be real with you. I tried the super-zoom route years ago with a Tamron 18-200mm F/3.5-6.3 Di III VC and unfortunately it left me pretty frustrated. The focal range is tempting, but the optical design means you sacrifice so much sharpness at the long end. I had issues with chromatic aberration in almost every shot I took in bright light, which was a nightmare to fix in post. If you really want to understand the numbers, focal length is just the magnification. 18mm is wide for those big Tokyo street scenes, and anything over 100mm pulls distant details close. Since you are worried about weight, you might look at the Sony E 16-70mm f/4 ZA OSS Carl Zeiss Vario-Tessar. It is not as long as the 135mm options, but the constant f/4 aperture is technically superior for consistency. I spent a whole summer with that glass and while the edge sharpness wasn't as good as expected for the price, the build quality and Zeiss glass contrast saved many of my shots. Sometimes it is better to have a lens that performs well across its range rather than one that just tries to do everything and fails at the optics. Just something to keep in mind before you drop your cash.

Honestly, if you want a true one-lens solution for Japan without carrying a heavy bag, you might want to look at the Tamron 18-300mm F/3.5-6.3 Di III-A VC VXD. It sounds like a lot, but having that 300mm reach is actually amazing for grabbing shots of temple details or busy street life from across the road. Be careful though, it is a bit heavier than the kit lens. I took a similar travel zoom on my own trip ages ago and my neck was killing me by day three, so make sure to get a decent strap. It pushes the budget a bit, but for the convenience of never swapping lenses in dusty or rainy conditions, it is totally worth it. Just practice a bit before you leave so you aren't fighting with the zoom ring while trying to catch a train.

Just saw this thread and honestly, people are making this way more complicated than it needs to be for a trip. Youre gonna be walking a ton in Japan, so do yourself a favor and keep it light. Like someone mentioned, balancing weight and zoom is key. Here is my two cents based on what everyone else said:

• If you go with the Sony E 18-135mm f/3.5-5.6 OSS, you get a super solid daily driver that wont kill your neck.
• Be careful with the massive super-zooms like the Tamron 18-300mm F/3.5-6.3 Di III-A VC VXD. They sound great on paper but can get really heavy when youre trekking through Kyoto all day.
• Definitely avoid cheap adapters. If you have extra cash, put it toward a decent UV filter to protect your glass from the dust and rain. Just bring a spare battery and maybe a small strap. Youll be fine.

Late to the party but wanted to jump in before you make a purchase. There are a lot of ways to go here, and honestly, the right choice really depends on what you value more when you are out walking around all day.

• Do you prioritize getting the absolute sharpest image possible, or is the convenience of not switching lenses your main concern?
• How much are you willing to compromise on weight versus the zoom reach you get? Before you drop your budget on something, it helps to know if you prefer a compact setup or if you dont mind a slightly larger piece of glass for better performance. Once I know that, I can give you a better idea of how the different manufacturers usually compare.

Yep, this is the way

Honestly, skip the fancy gear for now. In my experience, the Sony E 18-135mm f/3.5-5.6 OSS is the best bang for your buck. I've taken it on so many trips and it covers everything from wide city shots to tighter zoom. It's sharp, reliable, and fits perfectly in your budget if you snag a used copy. Keep your kit light and just enjoy Japan.