[thxbb12]

Well, a DX (or any APS-C) camera really begs for a dedicated ultrawide lens, because using full-frame ultrawides is usually not super efficient (sincerely yours, Captain Obvious). Or preferably two: one cheap and one more upscale, similar to how Canon EF-S users had a choice between the 10-18 (bottom feeder, plastic mount...) and the more posh 10-22.

In APS-C mirrorless, Fuji has quite a few nice UWA lenses (mostly the first 3 I'd say):

• Fuji 14mm f2.8
  
• Fuji 10-24 f4
  
• Fuji 8-16 f2.8
  
• Zeiss 12mm f2.8
  
• Laowa 9mm f2.8
  
• Samyang 12mm f2
  

For travel, the 10-24 WR f4 is probably the most interesting proposition.