How to detect how fast the camera is rotating??

Here is a code that prints camera rotation speed and movement speed, difference is that movement speed is not 0 when you are zooming in and out:

local RunService = game:GetService("RunService")
local Workspace = game:GetService("Workspace")

local currentCamera = Workspace.CurrentCamera

local previousCFrame = currentCamera.CFrame

RunService.RenderStepped:Connect(function()
  local cframe = currentCamera.CFrame

  local speed = (previousCFrame.Position - cframe.Position).Magnitude
  local _, rotation = (cframe * previousCFrame:Inverse()):ToAxisAngle()

  print(("Current movement speed of camera: %d"):format(speed))
  print(("Current rotation speed of camera: %d"):format(math.deg(rotation)))

  previousCFrame = cframe
end)

To get the movement speed you calculate distance between current camera position and camera position from previous frame, for angle I just stole the code here, since the result was in radians using math.deg I converted it to degrees, it's too hard of a math :o