VERT- Field of view scaling for Unity3D cameras.

VertMinusCameraFOV.cs

using UnityEngine;
using System.Collections;

/**
 * This class attempts to force VERT- Field of view scaling.
 * By default, Unity uses the HOR+ technique.
 * 
 * http://en.wikipedia.org/wiki/Field_of_view_in_video_games#Scaling_methods
 */

[ExecuteInEditMode]
[RequireComponent (typeof(Camera))]
public class VertMinusCameraFOV : MonoBehaviour {
	
	public float designTimeVerticalFieldOfView = 60;
	public int designTimeWidth = 1280;
	public int designTimeHeight = 720;
	
	private float hFOVInRads;
	
	private int prevWidth;
	private int prevHeight;
	
	void Start () {
		
		prevWidth = designTimeWidth;
		prevHeight = designTimeHeight;
		
		float aspectRatio = (float) designTimeWidth / (float) designTimeHeight;
		float vFOVInRads = designTimeVerticalFieldOfView * Mathf.Deg2Rad;
		hFOVInRads = 2f * Mathf.Atan( Mathf.Tan(vFOVInRads/2f) * aspectRatio);
		
	}
	
	void Update () {
		
		if (Screen.width != prevWidth || Screen.height != prevHeight) {
			
			float aspectRatio = (float) Screen.width / (float) Screen.height;
			
			float vFOVInRads = 2f * Mathf.Atan( Mathf.Tan(hFOVInRads/2f) / aspectRatio );
			
			Debug.Log("Screen resolution change. Recomputing aspect ratio (" + aspectRatio + ") and field of view (" + vFOVInRads*Mathf.Rad2Deg + ")");
			
			foreach (Camera cam in GameObject.FindObjectsOfType(typeof(Camera))) {
				cam.fieldOfView = vFOVInRads * Mathf.Rad2Deg;
			}
		}
		
	}
	
}

Thanks for this script! Exactly what I needed. Don't know why Unity doesn't support different FOVs in camera settings.