How do I edit this script such that the camera cannot zoom out at all?

local cg = script.Parent.CameraGroup.Value

local camdata = workspace:findFirstChild(cg)



if camdata == nil then
    camdata = Instance.new("Model")
    camdata.Name = cg
    camdata.Parent = workspace
end

if script.Parent.Parent ~= camdata then
    script.Parent.Parent = camdata
end

--Fixer for Up/Down type Security cameras:

script.Parent.CFrame = script.Parent.CFrame * CFrame.new(Vector3.new(), Vector3.new(-0.0001,0.0001,-1))

This is inside a ServerScript.

Any help is greatly appreciated, thank you.