Yes, as a Canon L-series lens, it features professional-grade dust and moisture resistance, making it suitable for use in challenging outdoor weather conditions.
Yes, it can be used on Canon EOS R series cameras with an EF-EOS R adapter and on Sony Alpha cameras using a Metabones or Sigma MC-11 adapter with full autofocus support.
This version (Mark I) uses a push-pull zoom mechanism and older IS technology, whereas the Mark II uses a traditional twist-zoom and offers up to 4 stops of stabilization.