Not that it's anything the same, but I just got back from my Alaska cruise. I left my 16-35/2.8II home and took a rented Zeiss 15/2.8 instead. Although I haven't had time to review my work yet, carrying four lenses for three bodies meant manual-focusing the Z15 was a challenge. I doubt you'd let a TS17 hang from your shoulder etc., but the focus ring on the Z15 was constantly bumped out of place so I had to recheck every time. Honestly, I suspect any shortcomings of the 16-35/2.8 were miniscule compared to the effort in handling the Z15. That's my $0.02.