Camera FoV

Hi,

I still got no answer about how to calculate the camera Field of View using focus and zoom.

I did some research and I find out how to calculate focalDistance, is it the same as the camera focus?

Here is formula I found how to convert diagonalFOV to focalDistance.

var diagonalFOV:Number = 25;

var width:Number = 622;

var height:Number = 310;

var w:Number = width  ;

var h:Number = height  ;

var d:Number = Math.SQRT((w * w) + (h * h)) ;

var focalDistance:Number = d * Math.TAN(diagonalFOV / 2.0) ;

If focalDistance is the same as the camera focus, it still doesn’t make sense how to calculate the correct camera zoom for one selected FoV.

Does anyone have some clue to this puzzle?

Thanks,

Marcelo Muniz