I'm trying to delete those ugly lines visible in the cylindrical shape of the lens. What is causing them is the added edge loops I made for the protruding detail with the switch. The problem is that if I delete those edges, it'll look even worse because of the n-gons. Any ideas?
I think your problem is how you place edge loops in your mesh over the curved surface.
Since it is a cylindrical surface edge loops cant be placed by simple subdivision, because that will yield a flat planar surface breaking the curvature of your otherwise cylindrical body.
When placing edge loops you need to make sure they are equidistant from the mesh center or use Subdivide Smooth for a curvature approximation.
Cylinders and spheres are prone to render errors when they contain faces of different sizes. In your case the switch also produces irregularities not only in the horizontal but also in the vertical direction (both top and bottom of the switch)
As far as I can tell your model is already made out of several objects/meshes. If it's not absolutely necessary to have the switch and the tube as one single object I would separate them and collapse the unnecessary edge loops.