How do I zoom the camera when it is in danger of colliding or being obstructed

I wan't to know how to make SphereCastAll work.

At the moment I am getting an error: Cannot implicitly convert UnityEngine.RaycastHit to bool

Any ideas?

(Original question: Hi. I am trying to find a way to detect objects that are in between my camera and my character.

I thought I could use the frustum of my camera as a template for a collision detection box and now I am trying to figure out a way to resize it to only detect what's in between my camera and my character, but when I try to scale the far clipping plane back I still detect collision from all my objects except when I point the camera straight up.

Can somebody tell me what's going on?

And maybe how I should detect objects?)

(Edit: I updated my code with the last answers fix.)

(Edit: I don't want to use the frustum anymore because it becomes unreliable when resized so I wil use a SphereCast instead)

Here is my code:

 using UnityEngine;
 using System.Collections;
 using System;
 
 public class Thir_Pers_CameraController : MonoBehaviour
 {
     // *Public*
     //Object to follow
     public Transform target;
     //Clamp angles (Keep it betwean 0 and 180)
     public float maxUp_dontPass180 = 0f;
     public float maxDown_dontPassZero = 0f;
     //Camera movement speed
     public float cameraSpeed = 1f;
     //Invertable axis
     public bool invertX = false;
     public bool invertY = false;
 
     // *Private*
     //Player input value variables
     private float camXinput = 0.0f;
     private float camYinput = 0.0f;
     //My up/down angle translation variable
     private float currentYaxis = 0;
     //Short version of clamp angles
     private float maxUp = 0;
     private float maxDown = 0;
     //Number versions of invertor axis
     private int invertorX = 1;
     private int invertorY = 1;
     //Camera
     //public Camera playerCamera;
     //Camera pivot points
     GameObject CameraPivotY;
     GameObject CameraPivotX;
     GameObject PlayerGravityPivot;
     //Objects with Ground tag
     //GameObject[] groundObjects;
     //Colliders of Ground
     //Collider[] groundColliders;
     //Camera frustum
     //Plane[] cameraFrustum;
     //Test frustum
     //public float frustumCollide;
     //Test far clip plane
     //public float farClipPlane;
     //Object that sphere cast hit's
     public GameObject sphereHitObject;
     //SphereCast radius
     public float sphereRadius;
     //SphereCast Max Distance
     public float sphereMaxDistance;
     //What has effect on sphereCast
     public LayerMask sphereLayerMask;
     //SphereCast origin
     private Vector3 sphereOrigin;
     //SphereCast direction
     private Vector3 sphereDirection;
     //Distance to object that has bean hit
     public float sphereHitDistance;
 
     void Start()
     {
         //Find cam X & Y pivots
         CameraPivotY = GameObject.FindGameObjectWithTag("CameraPivotY");
         CameraPivotX = GameObject.FindGameObjectWithTag("CameraPivotX");
         //Find graf pivot
         PlayerGravityPivot = GameObject.FindGameObjectWithTag("CameraGravityPivot");
         //Turn long into short clamp varibles
         maxUp = maxUp_dontPass180;
         maxDown = maxDown_dontPassZero;
         //Find camera Max distance
         sphereMaxDistance = transform.position.z;
     }
 
     void FixedUpdate()
     {
         sphereOrigin = CameraPivotY.transform.position;
         sphereDirection = -CameraPivotY.transform.forward;
         RaycastHit hit;
         if(Physics.SphereCastAll(sphereOrigin, sphereRadius, sphereDirection, sphereMaxDistance, sphereLayerMask, QueryTriggerInteraction.UseGlobal))
         {
             sphereHitObject = hit.transform.gameObject;
             sphereHitDistance = -hit.distance;
             transform.localPosition = new Vector3(transform.localPosition.x, transform.localPosition.y, sphereHitDistance);
         }
         else
         {
             sphereHitObject = null;
             sphereHitDistance = -sphereMaxDistance;
             transform.localPosition = new Vector3(transform.localPosition.x, transform.localPosition.y, sphereHitDistance);
         }
         /*
         //Find all Ground objects
         groundObjects = GameObject.FindGameObjectsWithTag("Ground");
         //Get colliders of Ground objects
         groundColliders = new Collider[groundObjects.Length];
         for(int i = 0; i < groundObjects.Length; i++)
         {
             groundColliders[i] = groundObjects[i].GetComponent<Collider>();
         }
         //Get playerCamera frustum
         cameraFrustum = GeometryUtility.CalculateFrustumPlanes(playerCamera);
         //Change far clip plane into camera distance to player object
         cameraFrustum[5].distance = -Vector3.Dot(cameraFrustum[5].normal, transform.position);
         //Read far clip plane
         farClipPlane = cameraFrustum[5].distance;
         //Check if there is Ground in frustum
         for (int i = 0; i < groundColliders.Length; i++)
         {
             if (!GeometryUtility.TestPlanesAABB(cameraFrustum, groundColliders[i].bounds))
             {
                 if(i == groundColliders.Length - 1)
                 {
                     frustumCollide = 0;
                 }
             }
             else
             {
                 i = groundColliders.Length;
                 frustumCollide = 1;
             }
         }
         */
         //My user preference camera invertor script
         invertorX = (invertX) ? -1 : 1;
         invertorY = (invertY) ? -1 : 1;
 
 
         //Get cam control inputs
         camXinput = Input.GetAxis("Mouse X") * invertorX * cameraSpeed;
         camYinput = Input.GetAxis("Mouse Y") * invertorY * cameraSpeed;
         
 
         //*Camera move left and right (for some reson up and right are inverted)
         CameraPivotX.transform.Rotate(Vector3.up * camXinput, Space.Self);
         
         //My currentYaxis varible wich reads the left/right angle of my camera and translate's it to a straight 0 to 180 (it doosn't have a full 360 degrees but 2 halfs of the same value)
         if(CameraPivotY.transform.localEulerAngles.x >= 0 && CameraPivotY.transform.localEulerAngles.x <= 90) //Test if camera angle is in the second quarter (wich reads too low)
         {
             currentYaxis = CameraPivotY.transform.localEulerAngles.x + 90; //Set the angle higher
         }
         if(CameraPivotY.transform.localEulerAngles.x >= 270 && CameraPivotY.transform.localEulerAngles.x <= 360) //Test if camera angle is in the first quarter (wich reads too high)
         {
             currentYaxis = CameraPivotY.transform.localEulerAngles.x - 270; //Set the angle lower
         }
 
         //*Camera move up and down combined with a clamping script wich uses my currentYaxis varible to determine where to clamp (it can't use a clamp value higher than 180 or below 0 becouse of my variable issues mentioned earlier)
         if (camYinput < 0) //Check if player moves camera down
         {
             if (maxDown > (currentYaxis + camYinput)) //Test if player input causes camera angle to move past MaxDown
             {
                 CameraPivotY.transform.Rotate(Vector3.right * (currentYaxis - maxDown) * -1, Space.Self); //Set camera angle to Max
             }
             else
             {
                 CameraPivotY.transform.Rotate(Vector3.right * camYinput, Space.Self); //Move the camera
             }
         }
         else if (camYinput > 0) //Check if player moves camera up
         {
             if (maxUp < (currentYaxis + camYinput)) //Test if player input causes camera angle to move past MaxUp
             {
                 CameraPivotY.transform.Rotate(Vector3.right * (maxUp - currentYaxis), Space.Self); //Set camera angle to Max
             }
             else
             {
                 CameraPivotY.transform.Rotate(Vector3.right * camYinput, Space.Self); //Move the camera
             }
         }
     }
 }