Jo, I might suggest reading the book "Light: the Science and Magic".
Jon, I might suggest taking your own advice.
Or, do some simple tests within a controlled environment. Use a basketball if nothing else. Better yet, a wet basketball.
I don't know what your wet basketball fetish is, but I run experiments like this all the time with a nice Grennaker mannequin.
Now take a picture using direct flash, no Sto-fen, no nothing. You can do it outdoors but do it when the flash is the principle/defining light source so as to better judge the characteristics of the light. We know that a direct, point light source is the least flattering light. Now add a Sto-fen diffuser to the flash and note the differences.
I have done exactly that experiment before. And guess what, Jon?
There is no difference!
None at all. Not even with the slightly larger Gary Fong diffuser.
You will have less contrast, less direct reflection (especially off the water).
No, you won't. You will have absolutely zero difference. If you've done this experiment, and you've seen a difference, it's because you've screwed up metering the flash and you've got a different ratio of ambient to fill.
It really is that simple.
Yes, it really is, once you get past the concept of you being wrong about pretty much everything.
Diffusion lowers contrast and direct reflections.
Diffusion doesn't make the path of light rays change in mid air.
It is easy enough to test.
Yes, it is easy enough to test. You should try that, yourself, because you're making it pretty obvious that you haven't done the test.
Of course at this point it is still a small light source, I'm not arguing that. But it will have an effect on the light characteristics.
No, it really, really won't. Since you mentioned LS&M, draw a family of angles for something the size of the Sto-Fen at a normal shooting distance.
There's no magic that lets a Stofen or a Gary Pong make light rays bend around in space and approach the subject from multiple angles.
I never claimed otherwise.
You've claimed that there's an effect. An effect, without science to explain it, is magic.
So far as I know, even a 6' Larson softbox won't bend light.
So a Sto-fen diffuser will diffuse the light, which is to say it will lower contrast and reduce direct reflections,
No, it won't, because it won't noticeably increase the size of the light in relation to the subject. The light source remains, effectively, a point.
Jo, take a flashlight an point it at a baseball.
Now put a thin sheet of white paper right over the flashlight. What happens? Diffusion. Less contrast. Less direct reflection. Take a beauty dish.... why do they make socks for beauty dishes?
Because they're typically 18-30 inches in diameter, and they produce a highly collimated light.
Why don't they make socks for speedlights?
What effect do you think that sock has on the light characteristics? It certainly doesn't make it a larger light source!
The trick to all of this is in the definitions; which is why I defined my words!
But you defined your words incorrectly, in ways that people skilled in science of optics or the art of photography cannot agree with.
--
Rahon Klavanian 1912-2008.
Armenian genocide survivor, amazing cook, scrabble master, and loving grandmother. You will be missed.
Ciao! Joseph
http://www.swissarmyfork.com 
