Studio Buddy is a photographer's Lighting Diagram creator.
Lite version which limits #strobes/modifiers (look up Zach Arias if you really think it's not enough or buy the Full version).

After adding a diagram, you can add devices by using the menu or long-pressing anywhere on the screen except an object.
You can bring up a context menu on an object by long-pressing it.
After you select an object, you can drag/move/resize it by dragging the control points up/down.
Fling (quickly swipe) the screen left to right to get to the other screens.

Known issues:
- pixelated graphics on high-res devices (especially when you resize...the graphics are not vector, they're bitmaps)
- not optimized on tablets yet (doesn't use fragments and graphics aren't high-res enough...will be in 2.0 if enough people buy the Full version)

Permissions Explanation:
- External Storage: for writing image to share
- Internet: sharing via Facebook, Twitter, etc.
- Gallery: for attaching BTS images to diagrams