UV filter for lens protection?
The most common argument is: the vast majority of today’s lenses already has UV filter in their lens coating and anyway, even modern camera sensors filter UV. That is 99% true. And maybe you really don’t have to worry about the remaining 1%. But we often want UV filter in front of our lenses not because of its capacity to filter out UV light, but to protect our lens from the elements.
The other most common argument is: any high quality lens is produced to endure natural elements like dust, wind, sand, water, etc. This is also true to some extent. The question really is, how much do we want to risk our expensive investment? I guess everyone has a different tolerance when it comes to use our equipment in hard and bad conditions.
Image quality
Probably the oldest advice is, never put any unnecessary glass in front of your lens. And in essence this is a wise way of thinking. The usual answer for this: “don’t worry about the quality, 99.9% of the population will only see your pictures on a tiny phone screen anyway”
Well, this is mostly true, but I have a few problems with this argument. First, as a photographer I don’t make pictures for phone screens. I know most images will be seen on some phone screens, but I want to produce quality that is great on tablet, or calibrated screens, or in print. Just because today’s habit is to scroll through a timeline and only pay attention for a second doesn’t mean that this is going to be the future. Maybe in 10 years it is going to be “trendy” to really pay attention to photographs. Maybe we will print much more than today. Maybe we will have super high-quality calibrated screens everywhere. Who knows? I’m not suggesting that every photograph we make deserve to be seen on the highest quality screen or print possible, but I believe every photographer passionately produce images. And that is alone worth some attention. Even if today’s photo consuming habits are not about quality.
I tied a few filters and analysed the results and come to the conclusion that only really cheap filters produce visibly bad results. B+W, Zeiss, Nisi or I believe any other professional brand nowadays produces filters we can safely use without worrying about image quality.
Everyday usage vs. harsh conditions
Even if we only use our cameras in relatively good weather, we still encounter lower-higher temperatures, wind, dust, rain. Of course even cheaper equipment can endure those to some degree. The more expensive and more professional a camera and the lens are we expect it to withstand any harsh conditions better. Yet, accidents may happen and honestly, quality lens is very expensive these days. Even though most lenses are weather sealed, maybe it is a good idea to protect the front lens when you’re out in the rain, especially if you have rain and heavy wind. Probably your lens will survive these things, but if you ever shot under those conditions you might know that these can really make your lens dirty. The same goes for wind the sand for example. Sand is even worse in my opinion. It can stick into the smallest places like in the tiny slit at the aperture ring or focus ring, or in the filter thread of the lens. It’s really hard to get rid of it completely. And if you happen to be in the desert it can be even more dangerous. Sand, in extreme cases, can ruin the coating of the front lens. I know it sounds extreme but it can happen. Compared to any lens, a filter is really cheap. So why not just use a filter in front of your lens under these circumstances and never worry again? Even if the terrible conditions ruin your filter, you’ll loose some money, but the lens will be just fine. I’'m aware that this is rare. But rare doesn’t mean never.
Use it or throw them out?
I don’t have the definitive answer but I can tell you my opinion. In normal environments I won’t use a UV filter for protection. I think today’s lenses are built to last, and under normal usage there’s no chance anyone will encounter a problem. If I know I’ll be in harsh environment: between sand dunes, storm, heavy wind with moisture and dust or industrial environment I use a high-quality UV filter for protection. The filter is small, hardly occupies any real space in your bag and it can protect your lens surface from being scratched or damaged. Even if the filter only protects your lens coating, you win. Buying another filter is cheap, buying another lens is very, very expensive.
See you soon, enjoy taking photos!
Tamas