Camera field of view and Mathf.Lerp, camera FOV not moving to value specified

Hello!

I'm using mathf.Lerp to change the camera FOV smoothly when the player hits a trigger. The script I have written for this does work, however the FOV is not changing to the value specified in the script and never goes below 30f.

I have the default FOV set to 40 and the target FOV set to 15. When the script is triggered the FOV changes from 40 to 30. I tried lowering the target FOV to 5 and but the lowest it will go when the script is ran is 27.

Am I using mathf.lerp incorrectly or should I be using something else?

Here's a snippet from my script:

 private float targetFOV = 15.0f;
  private float defaultFOV = 40.0f;
  public float speed = 0.2f;
 
  if (legsTrigger.isTriggerOn == true)
         {
             Camera.main.fieldOfView = Mathf.Lerp(Camera.main.fieldOfView, targetFOV, speed * Time.deltaTime);
         }
         else if (!legsTrigger.isTriggerOn)
         {
             Camera.main.fieldOfView = Mathf.Lerp(Camera.main.fieldOfView, defaultFOV, speed * Time.deltaTime);
         }