I recently bought a Canon 80D with an 18-135mm kit lens. –The lens is almost as good as the reviews say it is.
This doesn’t mean I’m not going to buy a better lens, only that this one is good enough that I can wait until I’ve saved enough, and I find a smokin’ deal.
The lens starts out at 4″ in length and extends to something like 6″. This isn’t the same sort of problem that it is with my Tamron 150-600mm, but since I have a bad habit of putting the camera in the bag lens up, it could turn into a problem.
Lifting the camera by the lens is never a good idea, but when I put in in the bag, camera down, the lens is the first thing I grab. So I’ve forced myself to lock the lens, that way when I lift it out of the bag the lens doesn’t extend with a “thunk” if I happen to grab it wrong.
I’ve never damaged a lens that way, but I don’t want to take a chance. –Especially since the guts of most lenses are made of plastic.
The AF/MF (autofocus / manual focus) switch is necessary if you’re going to manually focus the camera on things like macro photography.
The stabilizer switch is primarily for use on tripods. Since the stabilizer is designed for handheld use, if you leave it in the on position while the camera is mounted or resting on a stable surface it can create problems.
And on a short lens like this one, the lock is mostly to protect the lens from being mishandled by a klutz like me.
Most lenses, come with a manual. My advice is at least look through it. Sometimes there’s even something useful in there.
And finally, the first thing to do when you buy a new camera is to Read The Fucking Manual.
That’s right boys and girls, it’s fucking manual, not fine manual.