2D Light Depth Calculator

Last time I talked about light depth and calculating it in one dimension, now I will add another dimension. The 2d depth calculator I have created lets you handle more complex scenarios and is more visual. The drawing is to scale, but the scale is whatever you want it to be. If you want to use centimeters, then each square represents a centimeter. If you want feet, then each square is a foot (a square foot more accurately). Each solid cintrifical line represents a full stop of light difference from the previous solid line. Dashed lines, available at greater distances represent 1/3 stops. The amount of light loss you are willing to accept from the front of the subject to the back of the subject is up to you.

To use the tool:
Determine an appropriate scale for your subject. ie. Shooting a car or group of people you may want to use feet. Shooting a lego design, you may want to use a lego standard, 1 stud. etc.
Measure your subject in the scale you have chosen. (A lego figure is about 1 stud deep, and 2.5 studs wide)
Using another piece of paper with the same grid on it, cut out your subject based on your measurements.
Place the cutout on top of the lighting calculator and move your subject around to find the perfect distance for your effect.

So if you move your subject real close to the light source, you will notice the front of the subject will be 1 stop brighter than the back. Move your subject back and now your subject bay only have 1/3 stop difference from front to back. But this is a 2D calculator, so you also see where the edges and corners start to drop in light.

Attached is a low res version. It will still work fine. So go ahead and print it full page.