Originally posted by barondla I have seen filters protect many lenses. you bang the edge of a lens just right and it will screw up the fine filter threads. With a filter on, the threads are usually saved. The filter will crack and glass must be removed. Then collapse the filter ring to remove. Lens is still fine.
thanks
barondla
The only time I have ever had a lens physically damaged was with just this scenario except my shattered filter scratched the lens coating and ruined my new lens, never fitted a 'protection' filter since then.
My cameras have had white hot spelter bouncing off them when I had a contract with British Steel in the '70's, played havoc with the leatherette, just bounced of the lens with no damage, down mines in the '80's recording the aftermath, and all the dust, following explosions, recorded restored steam engines for decades all without a 'protection' filter, I have never damaged a lens in 50 years, I still have (and use) all of them, except, of course, the first one early in my career (1960's).
I have come across many occasions of flare caused by filters, just take your camera out in any town centre after dark and take a scene with street lights in shot.
When shooting with the Sun in shot if you see images with multiple 'ghost' images of the aperture you can bet your bottom dollar they had a filter on the lens. Flare is caused by light reflecting around inside the lens, usually off the aperture, it normally this finds it's way strait out of the front element never to be seen again, with a filter fitted it reflects off the flat rear surface of the filter and back into the lens again and again and results in the multiple 'ghost apertures' in the image.
I bought a Sigma 70 - 200mm f2.8 lens from a work colleague because it was rear focusing, removing the filter also removed the rear focusing issues and I got a bargain.
The best physical protection for a lens is the lens cap, after that a rubber lens hood which tends to put itself in the way of any sideways blows and cushions them.
Sorry to say it, but if you damaged a lens coating when cleaning then you must have had some grit under your finger and applied pressure and motion. Something you just don't do. Most lens cleaning is unnecessary, lenses don't need polishing, their surface should be matt, they are designed to absorb light not reflect it.
Controversial I know. I apologise in advance.
Chris