Field of View in relation to the Z axis in effects promoted to 3D

Hi there,

Anyone know what the Field Of View is in the Effects Editor when an effect is promoted to 3D?

I have a project where the resizes have been done in the Z position axis rather than Scale and we need to have a formula to convert the Z axis position to a Scale size percentage for the Online/Conform.

Anyone had to do this before?  Is there a simple formula I can use to generate the scale values?

Here's a table of various increments of Z and what the scale would need to be to match it (figured out manually - not too keen to plot any more this way as there are quite a large number of shots with varying sizes - could take some time...)

if Z = -999 scale = 20

if Z = -750, scale = 25

if Z = -500, scale = 33

if Z = -250, scale = 50

if Z = 0, scale = 100

if Z = 25, scale =111

if Z = 50, scale = 125

if Z = 75, scale = 143

if Z = 100, scale = 167

if Z = 125, scale = 200

if Z = 150, scale = 250

if Z = 175, scale = 334

Any help here would be greatly appreciated,

Thanks very much,

Jonno