With such a near parallel beam the light does not derive anymore from the light, the instrument. It is to be seen as a virtual light source from way behind the fixture.

How do we define this?

We elongate the outer rays of the beam backwards until they cross and that is where the virtual light source is active with the dedolight PB70 - this is between 6 and 20 meters behind the instrument.

This enhances the distance from the effective light source to the object and thus it diminishes all the ill effects of the square law. When our actors move the change of intensity is less noticeable than we've known before

This inverse Square law, as you know, is defined double the distance one quarter of the light. 

Now we know different ways to overcome these deficiencies; but dedolight Lightstream with the PB70 light this is also a very effective tool in this matter.