But this not change anything about the useless filters. They don't protect the glases. If the filters broke by an impact of something, do you expect that the front glas will be secure? Fragments of broken glas are very sharp and hard - this ftragments damage the front lense finaly.
I don't wrote that you or others doing wrong using window glas as a protection for the lense. I wrote that this glases are not required. If you handle with care, nothing will happens with the entire gear.
I do photos since 1978 and never damage something of my gear - especialy not the front lenses. It's happened that i touched the frontlense and got a finger print on them. Well, you don't see this on teh pictures. Later at home i had cleaned them. Does'nt matters.
Finaly, you must knwo what you are do or not. I would not extra pays for such useless filters and i don't recomment to use them.
Ironic that we are reviving a thread dedicated to a LENS THAT CANNOT TAKE A FILTER by continuing to debate the use of filters.
I made a decision to buy the 10-20mm f/4 despite not being able to protect the
bulbous front element (makes me tingle to type it!) But I keep an extra Canon lens cap for this particular lens in my car at all time, in case I misplace the original. And I make sure to re-cover the
bulbous front element (ooh, la la) the moment I finish with captures. And, beyond frequent dusting with a blower, I am painstakingly careful while occasionally cleaning the lens. I don't like having to be so careful with the coating of this lens, but this is a reasonable compromise I'm willing to live with in order to use such a great, fun lens.
Some people ask, "How can you care so little about ultimate IQ with a lens that costs so much money that you'd put a $75 piece of glass over its exquisitely engineered optics?" I ask, "How can you worry so much about a virtually indetectable IQ difference that you aren't willing to put a protective, $75, precision engineered, multi-coated filter over the delicate front-element?"
I'm not evangelizing, just suggesting we can all make up our own minds about it.