OK...
This turned out to be a bit more complicated than I expected and I ended up forgetting the idea of doing it as a video and I did it as a written tutorial instead
It's a subject that could go on for ever but I've kept it as simple as possible.
Here
Hi Garry. Just read the article, many thanks for the time taken. One dumb question I have is_______________ As you move the light away I get that we loose quantity of light so you open up the aperture am I to assume that if I required the same aperture eg: for dof reasons you would increase flash power ?
Gaz
Good point, thanks for that - now updatedOnly skim-read it Garry but looks good
The first three head shots show a lot. Maybe equalise exposures on say the forehead? Then the background on the last shot would be lighter, as it should be.
Don't call it photo physics or something like. It will bring up images ou programmes that ran in the night on BBC2.
Karl Taylor has already done something similar
http://petapixel.com/2014/07/01/inverse-square-law-light-explained-simple-terms-photographers/
If it got much more complicated than that then it would turn a lot of people off.