In this article, we will run through what a UV filter is, what its purpose is and whether you should use one or not.
Read on for all the information you need.
What Is a UV Filter?
According to the Wikipedia definition, “Ultraviolet (UV) is electromagnetic radiation with a wavelength from 10 nm to 400 nm, shorter than that of visible light.” Primarily, it comes from our natural light source, the sun.
An ultraviolet filter stops these rays from hitting the film plane or digital sensor.
How Does a UV Filter Help Your Photography?
Cuts Out UV Light
Back in the days of film, UV light would cause unwanted effects on images, as film is sensitive to UV.
The colours would shift (usually towards a purple-blueish hue), details would be hazier and less sharp.
A UV filter was the easiest solution to prevent such issues.
Protects The Lens
The great thing about a filter at the front of your lens is that it acts as a barrier. Not only to dirt, dust and smudges, but also to serious bumps and damages.
Smashing a lens accidentally on its front will smash the glass. That glass can be a $20 filter or your very expensive telephoto lens.
Of course, a UV filter won’t save your lens from serious drops. In that case, you can convert it to a cup:
Picture this. You are out taking photos and it starts raining. Your bag is out, all over the floor, and you have to collect all of your stuff scattered around.
You sling your camera on your back, throw everything you can into the bag, and head to the car. Working your way past some other cars, you run past a brick flowerbed, and that’s when you hear it.
Now, you have a huge scratch in your glass. Thankfully, you have your UV filter on, saving your expensive lens and only destroying your filter. That is a fair trade-off in my book.
Disadvantages of Using a UV Filter
No Advantage in Image Quality
Having a UV filter on a digital camera is not necessary for cutting out UV light.
Digital sensors are designed to be largely insensitive to these particular wavelengths.
Filters also need careful attention for cleaning, can trap dust between itself and the front glass element of the lens. And they cost money.
Loss of Quality
Unless you’re using a very good quality filter, filters can degrade sharpness significantly.
You might not notice it on an 18-55mm kit lens, but on anything sharper it’s prevalent.
Flare and Ghosting
Adding more reflective items to your lens has the capacity to add more surface to bounce light from.
A UV filter can pick up stray light and bounce it back. It may even create ghosts in very direct light.
Lenses already contain numerous glass elements inside, so adding more doesn’t help, but exacerbate the situation.
Loss of Light
UV filters come in all kinds of price ranges, and therefore, all kinds of quality. A low-quality UV filter can have adverse side effects, such as noticeably reducing light.
The worst example I’ve encountered was a half stop reduction on a no-name filter.
Digital cameras no longer require UV filters, they are an extra cost and need attention, especially when it comes to cleaning.
On the flip side, there is no argument against using good quality filters. They can protect your lens, and they don’t reduce the exposure or sharpness of your image.
If you are using expensive lenses in situations that could be very people-heavy, where the landscape is unforgiving or otherwise, use one. Even better if you already have own one, as it incurs no extra cost.
If you need to buy one, make sure it is of high quality to ensure your images are not affected by it.
Read our full guide to lens filters for more more information!