For heaven's sake, does this forum utilize moderators who can just shut down threads that devolve from snippy answers to down right rudeness and nasty? I find it amazing that with all of the different suggestions about letting those who like filters and those who do not peacefully coexist, we still get the same few people unable to sleep unless they continue to browbeat all opposing views until they cave in. Some of you guys just will not draw a relaxed breath until you have pummeled the opposition into submission.

We have two or three guys in this thread who fancy themselves Einsteinian physicists. They talk incessently, loudly and condescendingly to we fools who are clearly too stupid to stop using filters. It is obvious that we are clearly lacking in our engineering skills and an understanding of the laws of physics and we are lacking the innate intelligence that these priviledged few have. It is their duty to save us from ourselves; it is being done to save us and therefore must, for our own good, be treated as idiots who don't understand and accept the gospel BS that is being slung around. After all, several people sent us to You Tube videos to luxuriate in that bastion of scientific research posted there. I understand that watching 4 You Tube videos will qualify you for admission to Princeton's Department of physics. Wow. Nothing like visiting a you tube blurb for a deep understanding of natural law.

I beg a moderator to lock the thread, thereby putting these unhappy and petulant people out of their agony caused by the unfulfilled attempt to gain 100% compliance on the subject. Thank the Lord that there is nothing in the Second Amendment that gives photographers the right to bear filters to protect their lenses.

There will be peace between Syria, Iraq, Iran and Israel before the argument of whether photo filters degrade images is settled.

And the answer is....

Yes, there can be noticeable difference in image quality.

It might be very, very minimal under the most ideal lighting conditions, such as the original poster set up and tested in the examples shown.

Under more challenging lighting conditions, a filter often can and will be more problematic. Over the years, I've seen and had to deal with that... In some cases it meant some extra post-processing work (which can be a big deal when you have 1000+ images to process). In the worst cases, I ended up trashing otherwise good images that likely would have been fine if no filter had been on the lens.

But it depends on the quality of the filter, too. Better glass and multi-coatings can make a significant differences. However, under the most challenging lighting, even a top of the line filter can cause an increase in image issues.

Meanwhile, realistically, a filter is merely a thin piece of glass that gives very little real world "protection" to a lens. Yes, it can be helpful in certain situations. But it has little value at all preventing damage from even modest impacts. (Do take the time to watch that video: https://www.youtube.com/watch?v=P0CLPTd6Bds&feature=youtu.be. Even though that's un-scientific too, it's far better comparison than just the two shots at the beginning of this thread.)

What's not mentioned in that video is that a broken filter actually can do damage to a lens... sharp shards of glass scratching a front element or the coatings on it.

The video does mention... and I agree... that in general a lens hood is far more effective protection when shooting (and so long as it's properly fitted, cannot possibly do any harm to images). And a lens cap does a considerably better job of protection, when storing the lens. In fact and sort of ironically, when using a filter it is even more important to use hoods and caps!

So, decide for yourself and do whatever you want. I have UV filters to fit most of my lenses on hand in my camera bag and selectively use them for "protection". I'll install them in particular situations (sand storms, at the beach, etc.) where they actually might do some good... Situations where the possible benefits of the filter outweigh the possible negative consequences to my images.

I don't find I need to use those protection filters very often. I have other filters that actually serve a real photographic purpose and see a lot more frequent use (circular polarizers, neutral density, portrait special effects, etc.). And I virtually always use lens hoods... and keep my lenses capped when they are stored.

The problem with this thread is that anyone can set up a single instance where it's impossible to tell the difference in an image, where there is almost no way to tell whether or not there is a filter on a lens. That might be interpreted by a reader to mean that in all circumstances, a filter will not do no harm to images and even that it's a good form of protection for one's lenses... neither of which is true.

I could just as easily set up a lighting situation where a filter causes significant image issues and degradation, to make the counter-argument. But I know from experience that there are some situations where a protection filter is useful. Yet I also know that, realistically, the protection provided by a filter is pretty minimal.

Again, you get to decide for yourself. So do whatever makes you happy.