The Optimo 17-80 shows a major vignette when trying to cover the 33.5mm Open Gate image circle.

Optimo 17-80 @ 17mm Open gate T4

Optimo 17-80 @ 17mm Open gate T4

17-80 Open Gate at 17mm T4 with 1.85 crop

17-80 Open Gate at 17mm T4 with 1.85 crop

Optimo 17-80 on alexa XT Open Gate at 25mm

Optimo 17-80 on alexa XT Open Gate at 25mm

Optimo 17-80 at 25mm on alexa XT Open Gate 1:85 crop

Optimo 17-80 at 25mm on alexa XT Open Gate 1:85 crop

Optimo 17-80 at 40mm Alexa XT Open Gate

Optimo 17-80 at 40mm Alexa XT Open Gate

17-80 @ 40mm with 1.85 crop

17-80 @ 40mm with 1.85 crop

Optimo 17-80 at 80mm on Alexa XT Open Gate

Optimo 17-80 at 80mm on Alexa XT Open Gate

Optimo 17-80 at 80mm on alexa XT Open Gate 1.85 crop

Optimo 17-80 at 80mm on alexa XT Open Gate 1.85 crop