Extremely Useful, when it works. – Artemis Director's Viewfinder Review

I have had problems with the app not being able to focus at all and only being completely out of focus. Other aspects of the app are nice, though the interface is somewhat clunky. Also it is annoying if you accidentally bump the screen the frame guides move off-center and there is no button to return them center without going in and out of menus to try and reset it. That said it is extremely useful on a shoot and for scouting. This feedback is from an iPhone 7.
Review by }}}krogh{{{ on Artemis Director's Viewfinder.