Sep 27, 2013 - Sydney based SmartLearnApps today announces the new version of LensTutorial for iPhone & iPad. LensTutorial 1.4 is a free app that allows to manipulate a photographic lens in a virtual environment. Play with new zoom values to investigate photographic opportunities. You can interactively slide focal length (zoom the lens), lens aperture and focusing distance. The app will show you how depth of field, angle of view and size of the model being photographed is changing according to your selection.