Lens Protection Filters - And Why You MUST Use Them!
What you see here is the result of my beloved 50 mm f1.4 lens taking a dive from an unsecured Lowepro pouch 4 feet onto a bare concrete floor! Needless to say I wasn't too pleased when I saw the result, but on closer inspection to lens appeared intact with no visible damage, which was confirmed with a quick test on camera.
Fortunately, the lens landed on the filter rim and attached lens cap which absorbed most of the force as you can see by the way the cracks have propagated through the glass. I was able to remove the filter glass retaining ring and pick out the damaged glass with forceps. I then blew away any remaining shards with a blower. Not a good idea to use a brush or cloth for fear of damaging the coating on the front element.
For the sake of 30 or 40 quid, do buy a good quality protection filter for each of your lenses - there's a reason that the sales person is recommending that you do, and it's not to put commission or profits in their pockets!
Have good day.