i get the struggle with weight vs reach! basically, i suggest the Fujinon XF 18-135mm f/3.5-5.6 R LM OIS WR over tiny primes or heavier zooms for reliability: - Weather sealing: Literal lifesaver in Alps rain!
- No swapping: Keeps ur sensor safe from dust.
- OIS: Makes handheld shots sooo stable... maybe? I've used it for years and it's definitely the safest bet. Love it!! gl

Seconding the recommendation above! I had a similar struggle before a trip to Rome last year. The reach on the Fujinon XF 18-135mm f/3.5-5.6 R LM OIS WR is highkey essential for architecture. But you might wanna consider the Fujinon XF 18-120mm f/4 LM PZ WR for $899. It's an internal zoom, so it wont feel front-heavy like the Tamron. Lesson learned: constant f/4 and internal zooming are game changers for travel!

Respectfully, I'd actually suggest a different approach. I brought the Fujinon XF 18-135mm f/3.5-5.6 R LM OIS WR on a trek through the Dolomites last year and tbh... it felt way too bulky for the X-S body style. Not to disagree with the others, but in my experience, that extra reach isn't worth the handling trade-off. I eventually swapped to the Fujinon XF 16-80mm f/4 R OIS WR and it's a total value beast. It's usually $799, but you can snag a mint used one for like $500. * Constant f/4 is sooo much better for consistency * 16mm is HUGE for tight European streets vs 18mm * The OIS is basically magic with the X-S20 IBIS Lesson learned: having that wider 16mm field of view saved way more shots for me than the 135mm reach ever did. Seriously, dont sleep on it for a one-lens setup. gl!

Late to the party, but as someone who prefers to handle my own gear calibration and firmware updates without sending stuff back to the manufacturer, I’m curious about your 'self-service' preferences. The Alps can be pretty unforgiving on electronics and seals, so reliability is key, right? I’d love to know a couple of things before I give my 2 cents:
- Are you looking for a lens that you can personally update or calibrate via a USB-C port or dock, or are you fine with the standard 'set it and forget it' approach of OEM glass?
- How critical is a fully internal zooming mechanism to you for keeping dust out of the barrel during those mountain hikes? Basically, knowing how much you want to handle the technical upkeep yourself versus relying on a professional service center later makes a huge difference, you know?

i would suggest the Fujifilm XF 18-135mm f/3.5-5.6 R LM OIS WR because that 135mm reach is literal gold for architecture. sharpness is actually fine on the 26MP sensor at f/8, but be careful with the Tamron 17-70mm f/2.8 Di III-A VC RXD for Fujifilm X since it feels way too front-heavy for long hikes. gl!

Honestly, I am still kind of a beginner with all this stuff but I have been worried about the same things for my upcoming trip. One thing I havent seen mentioned is how you actually plan to carry the camera? Are you using a neck strap or one of those clips that attaches to a backpack strap? I have noticed some things with my gear over the long term that you might want to be careful about before you buy:

• The zoom lens getting loose and sliding out on its own (lens creep) when you are walking around
• Getting dust or moisture inside the lens barrel because it expands and sucks air in while zooming
• Feeling like the camera mount is under too much stress if the lens is long and you are moving fast I dont want to sound too negative lol but I am always scared of breaking something expensive in the middle of nowhere. It would be a bummer if the lens you pick ends up feeling flimsy or gets gritty after just a week of hiking in the Alps. Knowing how you carry it might change which one is safest to get.

100% agree