Z cameras have "live view" all the time, either in the viewfinder or on the rear display. Zooming into the image works well (and can be put on Fn buttons to make a shortcut), as does focus peaking if one is attracted to that feature. Provided a lens such as the 400/2.8 AIS is attached to a good tripod/head, it should be a breeze to work with in conjunction with either Z body.