Unity CS0619とCS0200の解決方法が分からない

###エラー内容とコード
2つのエラーの内容:
Drag.cs(15,9): error CS0619: 'Component.camera' is obsolete: 'Property camera has been deprecated.
Use GetComponent<Camera>() instead. (UnityUpgradable)'

Drag.cs(15,9): error CS0200: Property or indexer 'Component.camera' cannot be assigned to -- it is read only

問題のコード:

C#
1using System.Collections;
2using System.Collections.Generic;
3using UnityEngine;
4
5public class Drag : MonoBehaviour
6{
7
8    private Vector3 moveTo;
9
10    private bool beRay = false;
11
12    // Use this for initialization
13    void Start()
14    {
15        camera = Camera.main;
16    }
17
18    // Update is called once per frame
19    void Update()
20    {
21        if (Input.GetMouseButtonDown(0))
22        {
23            RayCheck();
24        }
25
26        if (beRay)
27        {
28            MovePoisition();
29        }
30
31        if (Input.GetMouseButtonUp(0))
32        {
33            beRay = false;
34        }
35    }
36
37    private void RayCheck()
38    {
39        Ray ray = new Ray();
40        RaycastHit hit = new RaycastHit();
41        ray = Camera.main.ScreenPointToRay(Input.mousePosition);
42
43        if (Physics.Raycast(ray.origin, ray.direction, out hit, Mathf.Infinity) && hit.collider == gameObject.GetComponent<Collider>())
44        {
45            beRay = true;
46        }
47        else
48        {
49            beRay = false;
50        }
51
52    }
53
54    private void MovePoisition()
55    {
56
57        Vector3 mousePos = Input.mousePosition;
58        mousePos.z = 10;
59
60        moveTo = Camera.main.ScreenToWorldPoint(mousePos);
61        transform.position = moveTo;
62
63    }
64}