This is a question I've asked myself on several occasions, typically right after I fork over a fist full of cash for a fancy new lens: Are UV filters worth it? I'm going to cut to the chase on my answer: No. UV filters are not worth it. Before you tear into me because you vehemently disagree, let me make something very clear. This is my opinion. If you love your UV filters and couldn't imagine life without them, more power to you. But, I'm going to explain why I don't think UV filters are worth much.
The Original Purpose
UV filters where used in the film days to protect against the haze of ultra violate light. The thing is, modern lenses do this with advanced coatings now so there's no need screw on an additional piece of glass for this purpose. UV light won't effect your images, not in the modern age. So, why do people still buy them, you ask?
Yep, most people buy a UV filter to protect the front element of their lens. It's comforting to think that this thin piece of glass is going to break or scratch before the front-most part of your precious lens. Just screw one on and your safe. It's a prophylactic for your glass. That's why people buy UV filters.
Lenses Don't Need Prophylactics
Here's how I see it: lens designers went to great lengths to perfect these pricy pieces of glass. The coatings on that front element where thoughtfully engineered. Putting a piece of glass (or cheap plastic in some cases) in front of it changes its dynamics. There's no getting around that. Sure, the UV filter says it's super awesome and costs a lot of money (for very high-quality glass in some cases). But that wafer-thin filter was not a design consideration when the lens was made.
Maybe it won't effect image quality. Maybe it will. The fact that UV filters cause ghosting in direct sunlight is pretty well known and I personally like to use the sun as backlight in portraits. I don't want to be screwing around with a filter in those instances when I want the backlit effect. Also, if a filter does break on impact toward the front element, the filter itself will likely scratch the front element while shattering. You never know.
The front element of a lens is pretty durable but even if you do happen to get a scratch here and there, it probably won't effect image quality (the rear element is another story). Read about the torture test Kurt Munger put a lens through to illustrate this further. He really beat that thing and until it was destroyed, image quality was surprisingly unaffected until he pretty much smashed it.
I have owned a lot of lenses and frankly, I haven't scratched or broke a front element. Sure, not everyone has this experience, but that's been mine. Even so, you could get a front element repaired in the rare case that you shatter one. It won't be cheap, but it's possible to have it fixed.
Don't get me wrong, I'm very protective of my gear and that's the reason I've never had a lens scratched or broken (even my iPhone lens is pristine). I do protect my glass with a lens hood. 80% of the time I have a lens hood on. It gets removed if I want a smaller profile or if I want my lens to look less intimidating. But for the most part, the lens hood is on.
It would pretty damn difficult to harm the front element of a lens with a proper lens hood mounted. Oh, it's possible, but very, very unlikely. And with a lens hood, you can rest assured that you're getting maximum image quality, at the level intended by the lens designers. I like that. You might not mind the tradeoffs for the sense of security you feel a UV filter provides. I for one feel it's unnecessary. To each his own as they say.
Some Other Opinions
I have researched this topic and below are a few videos that I found helpful. Hope you do too:
1) Digital Rev - UV filter VS no UV filter
2) Carl Taylor - Are UV filters for your DSLR any good?
3) Matt Granger - UV Filters - A Waste of Time & Money
Cover image courtesy of Hamdan Mesfer Al Amimi