LensTutorial visualizes all changes you apply to lens controls by displaying cone of view with focus point put on the eyes area of photographic subject. Exact values of calculated parameters are displayed as well. Slide the controls and see how simulated world responds.
A very important property of LensTutorial is showing “it all” a once. There are apps that can show Angle of View, but for DOF you’ll have to download something different. There are apps that give you numbers but no visual clues. We’ve made the application more visual and understandable by designing it to be interactive, providing near-realtime response to change of lens parameters.