I know it's no problem for trained players, but I suspected that an instrument's ability to have its player worry about pitch exclusively on the fingerings might be what Quartesixte meant in their claim that a violin plays in all keys "naturally."
Interesting about woodwinds not being equally tempered! I see another commenter points out the same, so I take that back as an incorrect assumption. So I wonder why they wouldn't build them as such, given that it would reduce the worst-case required bending to achieve arbitrary-key just tuning. I think the octave key is typically the only critical use of the harmonic series (altissimo aside), and that's a perfect 1:2 in all systems so it's moot.
Interesting about woodwinds not being equally tempered! I see another commenter points out the same, so I take that back as an incorrect assumption. So I wonder why they wouldn't build them as such, given that it would reduce the worst-case required bending to achieve arbitrary-key just tuning. I think the octave key is typically the only critical use of the harmonic series (altissimo aside), and that's a perfect 1:2 in all systems so it's moot.