Nothing but a chart.
Be Careful: READ THE DETAIL
A Must Have App for the Serious Photographer
Without this tool, you are merely guessing on the decisions you need to make.
How many shots? Where are the shots focused? What f/stop?
Yes, photography is an art, but this part of it is a science. So if you want to get the very best results from your camera and lens, do yourself a favor and get this app.