Other problems:
1) first time you launch the app you see the gridlines briefly visible until the viewfinder is initialized
2) on N4, the grid lines are not aligned properly with the viewfinder, they start at the left edge of the screen, not on the left edge of the viewfinder. And they don't expand all the way to the right edge of the viewfinder.
3) switching to front camera with gridlines on will make the gridlines disappear until you tap on the screen
4) same problem when switching back to back camera
Other problems:
1) first time you launch the app you see the gridlines briefly visible until the viewfinder is initialized
2) on N4, the grid lines are not aligned properly with the viewfinder, they start at the left edge of the screen, not on the left edge of the viewfinder. And they don't expand all the way to the right edge of the viewfinder.
3) switching to front camera with gridlines on will make the gridlines disappear until you tap on the screen
4) same problem when switching back to back camera