Luce is an app that allows you to draw your lighting diagrams in easy way and wherever you want directly on your iPhone.
Luce is able to read exif metadata from the picture you associate so when you export your diagrams, you can see how you setted-up your camera too or you could set them manually.
Let's take a look to an example of a lighting diagrams exported from an iPhone with Luce v1.3.4 by clicking here