DOF Falloff Adjustments?

[biochemical_animations]

Is there a way to adjust the falloff of the dof for the vray camera? I understand the f-number effects this defocus area, but it seems to affect the focal area primarily, not necessarily the fallout curve. There are times when I would like to set the defocus spot, but then adjust falloff curve a bit, by tightening or loosening the falloff of the defocused spot...perhaps based on a bezier curve or something.

Anyway to do this, or am I not understanding the f-number entirely. TIA.

[Art48]

It is a physical camera so you can't do that at the moment. Depending on your scene you could do that in post with Frischluft Lenscare.