I'm wondering if the effect that fields have on particles is proportionally inverse to the size of your scene?
The reason I'm wondering about this is that I have a scene where I've had to increase the magnitude of the gravity field to 30 and the magnitude of the turbulence field to 500 to get any kind of meaningful reaction on my particles (which live for 3 sec rand 1.5).
Now, the scene constists almost entirely (so far) of a motion path, with an emitter that emits particles, that stretches over approx. 6500 units. It is this large, because getting a really dynamic and speedy feel to the object travelling through space, and the camera following it, somehow didn't really look too good with a smaller motion path.
I assume that if the above is true, then the same thing will apply even more to lighting...