Whenever I bought a new lens, I always added a UV filter to it. It was obvious to do so, and I never gave it any thought. But there was a moment that I stopped adding that sort of filter and I never looked back since. Does a UV filter still have any benefit, or is it a waste of money? Let’s find out.
You probably have heard about UV filters, also called Skylight filters (I never understood the exact difference between the two). These pieces of glass, screwed in front of a lens, reduced the amount of ultraviolet light which often resulted in better colors. This was many years ago before front lens elements became coated with all sorts of layers, thus rendering the UV filters useless.
These UV filters had a second task. It would protect the front lens element, preventing scratches or bursts in the precious glass. It was easier to replace a broken UV filter than a broken front lens element. Not to mention the costs involved. And it still counts, perhaps even more because lenses are almost 10 times more expensive than 20 or 30 years ago. Another benefit was protection against rain, dust, and sand. Just remove the filter and rinse it. You wouldn't want to do that with your expensive lens.
Today there is no need for filtering ultraviolet light with a UV filter anymore since the lenses have much better coatings. These coatings not only increase performance, it makes the glass very hard and resistant to scratches — up to a certain point of course. The new nano-coated lenses even have water resistance, as if drops don’t like to touch the surface anymore.
There are also a lot of lenses that won’t accept any filter. The rounded glass of an ultra-wide angle lens prevent any standard filter and rely on the hardened glass to give the protection it needs. As long as you don’t drop your lens, and use a proper lens hood if available, special protection filters are not really needed anymore.
But I can image you would feel better with a filter installed if possible. It still is an extra protective barrier. That is the only remaining reason for such a filter and that is why many filters are now called protection filters. But this extra glass can turn against you, so be aware. For example, I once jumped over a ditch and fell. My Canon EF 24-70mm f/2.8L lens hit a stone and I ended up with a dent in the filter threat. This small accident made it impossible to place a filter or filter holder.
Imagine what could have happened if I had a UV filter or protection filter installed. In that case the filter itself would have taken the hit, and I am sure it would have bended, just like the filter threat did in my case. Perhaps it would have become impossible to loosen the filter ring due to the damaged filter threat, and I am convinced the filter would have been shattered, with the risk of scratches on the front glass element by sharp broken glass pieces.
From this unfortunately incident I learned that a filter won’t always give the protection you would like to have. And in my case I believe there would have been even more damage when a filter was installed, rendering the lens useless.
There are more situations where I find a filter unwanted. Most of the times a protective filter is significantly less in quality than your expensive lens with its high-quality coatings. Often that small piece of glass increases the risk of flares. Especially when shooting sunrises or sunsets, flare can arise more easily with a filter. But also street lights at night can increase the amount of flaring when a filter is placed. In the worst-case scenario it even can counteract for all the anti-flare coatings of an expensive lens. Think of it this way: why would you put a $30 filter in front of a $2,000 lens? It is like the weakest link in a chain.
There is another drawback to filters. When you like photographing for an extended amount of time at night, like star trails, condensation can occur much sooner with a filter in front of the lens. Condensation originates when the temperature of your lens drops below the dew point. Since a lens has a lot of mass, it takes a while before it is cooled down. But a small filter will cool down a lot quicker. I have seen condensation occur on a lens with a filter within five minutes, while the lens of another camera next to it could continue to shoot without filter for three quarters of an hour before it was cold enough for condense to form. I made the time-lapse below to show how condensation can form while shooting images for a star trail.
Should you completely avoid using protective filters or UV filters? Perhaps not. Some lenses are only water resistant when a filter is placed. Especially those lenses that move inside the barrel when focusing require a filter to protect it from water. But it can also protect your precious lens when photographing on the beach with strong wind. The grains of sand have the tendency to sand blast the front glass element, making a matte glass out of it, rendering the lens completely useless. And of course it is much easier to clean when it gets dirty, just by removing the filter.
There is another good use for a UV filter. You can use it for making a DIY soft focus filter. Put a bit of wax, gel, or Vaseline on it and you’re done. Just try it out.
So don’t throw away your filter yet, but keep it at hand for occasions when you can have benefit from it. Just remove it when it is not necessary.
Do you have a filter on your lenses, and is there a special reason for it? Please let me know below in the comments.