Change camera view

Is it possible to somehow implement the standard Roblox view switching into this script? It doesn’t work now because the camera type is set to Scriptable.

repeat wait() until game:GetService("Players").LocalPlayer.Character ~= nil
local runService = game:GetService("RunService")
local input = game:GetService("UserInputService")
local players = game:GetService("Players")

-- you can mess with these settings
CanToggleMouse = {allowed = true; activationkey = Enum.KeyCode.F;} -- lets you move your mouse around in firstperson
CanViewBody = true 		-- whether you see your body
Sensitivity = 0.6		-- anything higher would make looking up and down harder; recommend anything between 0~1
Smoothness = 0.05		-- recommend anything between 0~1
FieldOfView = 80		-- fov
HeadOffset = CFrame.new(0,0.7,0) -- how far your camera is from your head

local cam = game.Workspace.CurrentCamera
local player = players.LocalPlayer
local m = player:GetMouse()
m.Icon = "http://www.roblox.com/asset/?id=569021388" -- replaces mouse icon
local character = player.Character or player.CharacterAdded:wait()
local human = character.Humanoid
local humanoidpart = character.HumanoidRootPart

local head = character:WaitForChild("Head")
local CamPos,TargetCamPos = cam.CoordinateFrame.p,cam.CoordinateFrame.p 
local AngleX,TargetAngleX = 0,0
local AngleY,TargetAngleY = 0,0

local running = true
local freemouse = false
local defFOV = FieldOfView

local w, a, s, d, lshift = false, false, false, false, false

-- you can mess with these settings
local easingtime = 0.1 --0~1
local walkspeeds = {
	enabled =		  true;
	walkingspeed =		16;
	backwardsspeed =	10;
	sidewaysspeed =		15;
	diagonalspeed =		16;
	runningspeed =		25;
	runningFOV=			85;
}

---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- 

function updatechar()
	
	for _, v in pairs(character:GetChildren())do
		if CanViewBody then
			if v.Name == 'Head' then
				v.LocalTransparencyModifier = 1
				v.CanCollide = false
				v.face.LocalTransparencyModifier = 1
			end
		else
			if v:IsA'Part' or v:IsA'UnionOperation' or v:IsA'MeshPart' then
				v.LocalTransparencyModifier = 1
				v.CanCollide = false
			end
		end
		if v:IsA'Accessory' then
			v:FindFirstChild('Handle').LocalTransparencyModifier = 1
			v:FindFirstChild('Handle').CanCollide = false
		end
		if v:IsA'Hat' then
			v:FindFirstChild('Handle').LocalTransparencyModifier = 1
			v:FindFirstChild('Handle').CanCollide = false
		end

	end
	
end

-- math, thx roblox wiki
function lerp(a, b, t)
	return a * (1-t) + (b*t)
end


---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- 

input.InputChanged:connect(function(inputObject)
	
	if inputObject.UserInputType == Enum.UserInputType.MouseMovement then
		local delta = Vector2.new(inputObject.Delta.x/Sensitivity,inputObject.Delta.y/Sensitivity) * Smoothness

		local X = TargetAngleX - delta.y 
		TargetAngleX = (X >= 80 and 80) or (X <= -80 and -80) or X 
		TargetAngleY = (TargetAngleY - delta.x) %360 
	end	
	
end)

input.InputBegan:connect(function(inputObject)
	
	if inputObject.UserInputType == Enum.UserInputType.Keyboard then
		if inputObject.KeyCode == CanToggleMouse.activationkey then
			if CanToggleMouse.allowed and freemouse == false then
				freemouse = true
			else
				freemouse = false
			end
		end
	end
	
	if inputObject.UserInputType == Enum.UserInputType.Keyboard then
		if inputObject.KeyCode == Enum.KeyCode.W then
			w = true
		end
		
		if inputObject.KeyCode == Enum.KeyCode.A then
			a = true
		end
		
		if inputObject.KeyCode == Enum.KeyCode.S then
			s = true
		end
		
		if inputObject.KeyCode == Enum.KeyCode.D then
			d = true
		end
		
		if inputObject.KeyCode == Enum.KeyCode.LeftShift then
			lshift = true
		end
	end
end)

input.InputEnded:connect(function(inputObject)
	if inputObject.UserInputType == Enum.UserInputType.Keyboard then
		if inputObject.KeyCode == Enum.KeyCode.W then
			w = false
		end
		
		if inputObject.KeyCode == Enum.KeyCode.A then
			a = false
		end
		
		if inputObject.KeyCode == Enum.KeyCode.S then
			s = false
		end
		
		if inputObject.KeyCode == Enum.KeyCode.D then
			d = false
		end
		
		if inputObject.KeyCode == Enum.KeyCode.LeftShift then
			lshift = false
		end
	end
end)

---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- 

runService.RenderStepped:connect(function()
	 
	if running then
		updatechar()
		
		CamPos = CamPos + (TargetCamPos - CamPos) *0.28 
		AngleX = AngleX + (TargetAngleX - AngleX) *0.35 
		local dist = TargetAngleY - AngleY 
		dist = math.abs(dist) > 180 and dist - (dist / math.abs(dist)) * 360 or dist 
		AngleY = (AngleY + dist *0.35) %360
		cam.CameraType = Enum.CameraType.Scriptable
		
		cam.CoordinateFrame = CFrame.new(head.Position) 
		* CFrame.Angles(0,math.rad(AngleY),0) 
		* CFrame.Angles(math.rad(AngleX),0,0)
		* HeadOffset -- offset
		
		humanoidpart.CFrame=CFrame.new(humanoidpart.Position)*CFrame.Angles(0,math.rad(AngleY),0)
		else game:GetService("UserInputService").MouseBehavior = Enum.MouseBehavior.Default
	end

	if (cam.Focus.p-cam.CoordinateFrame.p).magnitude < 1 then
		running = false
	else
		running = true
		if freemouse == true then
			game:GetService("UserInputService").MouseBehavior = Enum.MouseBehavior.Default
		else
			game:GetService("UserInputService").MouseBehavior = Enum.MouseBehavior.LockCenter
		end
	end
	
	if not CanToggleMouse.allowed then
		freemouse = false
	end
	
	cam.FieldOfView = FieldOfView
	
	if walkspeeds.enabled then
		if w and s then return end
		
		if w and not lshift then
			FieldOfView = lerp(FieldOfView, defFOV,easingtime)
			human.WalkSpeed = lerp(human.WalkSpeed,walkspeeds.walkingspeed,easingtime)
		elseif w and a then
			human.WalkSpeed = lerp(human.WalkSpeed,walkspeeds.diagonalspeed,easingtime)
		elseif w and d then
			human.WalkSpeed = lerp(human.WalkSpeed,walkspeeds.diagonalspeed,easingtime)
		elseif s then
			human.WalkSpeed = lerp(human.WalkSpeed,walkspeeds.backwardsspeed,easingtime)
		elseif s and a then
			human.WalkSpeed = lerp(human.WalkSpeed,walkspeeds.backwardsspeed - (walkspeeds.diagonalspeed - walkspeeds.backwardsspeed),easingtime)
		elseif s and d then
			human.WalkSpeed = lerp(human.WalkSpeed,walkspeeds.backwardsspeed - (walkspeeds.diagonalspeed - walkspeeds.backwardsspeed),easingtime)
		elseif d then
			human.WalkSpeed = lerp(human.WalkSpeed,walkspeeds.sidewaysspeed,easingtime)
		elseif a then
			human.WalkSpeed = lerp(human.WalkSpeed,walkspeeds.sidewaysspeed,easingtime)
		end	
		
		if lshift and w then
			FieldOfView = lerp(FieldOfView, walkspeeds.runningFOV,easingtime)
			human.WalkSpeed = lerp(human.WalkSpeed,human.WalkSpeed + (walkspeeds.runningspeed - human.WalkSpeed),easingtime)
		end
	end
		
end)

Elaborate on what you mean, try to provide image/video references

I mean, how to integrate the default zoom in and zoom out roblox camera system so that the player can enter and exit from first person?

Have a variable for zoom distance, manipulate the zoom distance based on scrolling wheel input / pinching on screen and then implement that to your camera. If you check the user inputs docs you can find relevant events to detect these