Originally posted by Fluegel The lens I am looking for would be 16 to 40 mm with F4.
DA 16-85 is your only option, but it's not ƒ4. Where are you walking around? The sharpest setting and the most useful DoF settings for these lenses are ƒ5.6 to ƒ8 if you're walking out doors. You can shoot up to 400 ISO without noise reduction, and 800 and 1600 ISO in a crunch, with minimal noise reduction. I'd suggest you rethink that.
Insisting on ƒ4 is kind of odd, unless you really want constant aperture, which is a thing for studio photographers, however, you indicated this is not a lens for studio use.