Protecting Your Lenses With UV Filters: We Review the Urth Plus+ to Settle the Argument

If one argument gets photographers riled, it’s whether one should protect the front element of a lens with a UV filter. Should we instead use a lens hood? Let’s settle the argument with this definitive answer by testing an Urth Plus+ pro filter.

Last week, I bought an Urth Plus+ UV filter. I use their ND filters and am impressed with their optical qualities. Historically, I had used their UV filters too. My reason for stopping was partly because a one-time camera company representative told me that the front elements of their lenses were much more robust and, consequently, had greater resistance to damage. However, I see OM Digital Systems – the camera brand I use – and Nikon, Canon, and Sony are all manufacturing their protective filters. If the lens manufacturers sell their own protectors, there must be a reason. Should I start protecting my lenses with filters again?

The History of the UV Filter

Back in the days when film cameras ruled, we used to fit skylight filters to our lenses. The filters had a very slight magenta hue and would counter the blue cast that would show up on film when shot in daylight. There were two common types: 1A and the slightly darker 1B filters. One would choose a stronger UV filter if shooting in conditions with intense UV light, such as at high altitudes.

These filters had a secondary function: they protected the lens’s front element from damage.

With the arrival of digital cameras, arguments started to break out. Firstly, digital sensors were not prone to the ghosting haze caused by UV light on film. Secondly, the auto white balance in cameras is outstanding, so the blue cast from the sunlight is automatically corrected. Then thirdly, and this is where the controversy stems from, it was argued that the increasingly improved resolution of both sensors and lenses meant that lower-quality glass placed in front of the lens would degrade the image quality. I wanted to prove or disprove this theory, so I put a UV filter to the test.

The Arguments for Using a UV Filter

I have real-life examples of why using a filter is a good idea:

• I do a lot of shooting on the beach. One night, I was shooting a fireworks display by the sea and noticed the lens had spray droplets on it. I carefully dabbed them off to continue shooting but still scratched the front element; sand must have been present too.

• A couple of years ago, I bought a legacy Zeiss lens attached to a camera for very little money from a market stall holder. The person at the stall told me the lens was broken. I like experimenting with old film equipment, so I bought the camera without looking too closely at it. It cost the equivalent of around $7. When I got the camera home, I discovered it was just a smashed UV filter. That sacrificial piece of glass had done its job and saved the lens.
• I was shooting an evening event, and a child was interested in my photography. Always keen to encourage youngsters, I let him look through the viewfinder, and he immediately pressed his greasy fingers to the glass. It was my fault; I should have instructed where to hold it. But cleaning a filter would have been much quicker than carefully de-greasing the lens, which was out of action for the rest of the shoot.
• A relative of mine is a wedding photographer. He bought a new pro lens for his camera, and on the first shoot he used it on, a bridesmaid sprayed it with hair lacquer.
• Additionally, a UV filter can help to cut through the haze on a summer's day.

Those are the reasons I started using high-quality UV filters to protect the lenses. At the time, I didn’t carry out any measured image-quality comparisons, but there seemed to be no difference between the images I shot with the filter and those without.

Filters Can be Faulty

I once did buy a filter that produced strange artifacts in the photos. This was particularly noticeable with any out-of-focus balls of light. They had pronounced lines running across them.

I contacted the manufacturer and sent them photos demonstrating the issue. They said it was a manufacturing fault and sent me a replacement. That solved the problem. The replacement was better. But, looking at my back catalog, my newer equipment and the Urth Plus+ filters give better results.

Recently, I visited a Facebook photography group I sometimes drop into. Someone was complaining about the image quality of their new lens compared with the one they had borrowed. Looking at the sample shots, I could see ugly artifacts like those I had observed. I asked the photographer if they had fitted a UV filter. They said they had. It was a Tiffin, so it should have been good quality. Removing the filter solved the problem. She bought another, and that showed no issues at all. Clearly, UV filters can suffer from manufacturing faults like any product.

Do Lens Hoods Offer Better Protection?

Many photographers swear by using lens hoods instead of UV filters. Hoods are designed to stop sunlight from falling on the glass from an oblique angle, which can fog your images and cause unwanted flaring. They can protect the lens’s front element against impact, falling rain, and accidentally rubbing against clothes. Furthermore, they are not adding a layer of glass in front of the lens, which might affect image quality.

However, like UV filters, they are not designed for those additional protective purposes.

Many quality lenses are made so that the part that holds the front element in place will sacrificially shear off in an impact, thus protecting the rest of the lens. It acts like a crumple zone in a car. A lens hood increases the leverage making this more likely. I have had it happen. Moreover, hoods don’t offer perfect protection for the front element. Someone I know dropped a camera onto a rock. Despite having a hood fitted, the glass still cracked.

For me, it has not been an either/or debate. I’ve used both. Previously, I have replaced scratched filters that have protected my lens from damage, and I invariably have a lens hood attached to the lens, which has offered some protection too.

The Filter Tests

I chose the best-quality Urth Plus+ filters for this experiment. I like Urth. They are an environmentally positive company, which is essential for me. They plant trees in rainforests with every purchase; over a million have been planted so far.

For comparison, I also acquired some cheaper filters. Some I was given, and I bought a couple too.

To start the tests, I mounted my OM System OM-1 fitted with the 12-40mm f/2.8 PRO lens on my tripod overlooking the water with the sun reflected on it. I shot in aperture priority at f/5.6, so I would get a constant behavior of the lens. I dropped the lens out of focus, underexposed, and photographed the sunlight sparkling on the water, as this would highlight any optical defects.

I started with the cheaper K&F Concept, Hoya, and Kood filters. In the resulting images, concentric rings appeared within and around the balls of light. Then, a slight softness was apparent when I focussed the lens on subjects. The drop in image quality is sufficient for me to conclude that I would never use them.

So how about the more expensive filter?

Using the Urth Plus + (professional standard) UV filter, I could see no difference in image quality between having the filter fitted and not.

The out-of-focus balls of light were broken, which was to be expected because the water moved organically, and the reflected light was uneven. However, there was no repeating pattern or banding visible. In later tests, I pointed the lens at an out-of-focus LED, and the result was clean. Not so with the cheap filters.

In later tests, I pointed the lens at an out-of-focus LED, and the result was clean. Below, the first image was with no filter, and the second, on the right, with the Urth. I shot this handheld, hence the slight difference in size. The LED in the photo is rectangular, which accounts for the horizontal lines just visible.

On my first day of testing, the sun was constantly disappearing behind clouds, so the light levels frequently changed. Consequently, other comparative tests were difficult to make. However, images shot with and without the Urth filter were as sharp as each other.

The above two seascapes were shot a few seconds apart. The one on the right was with the filter fitted. the slight changes in the lighting were due to the fast-moving clouds. Later tests showed no color changes when I added and removed the filter.

In the above slider, the left-hand image has the filter fitted.

The flowing morning, the weather was calmer, and I managed to shoot some images with the filter on and off the lens. There was no change in the white balance. There was no additional lens flare when pointing the camera almost directly at the sun.

Back home, I tested the exposure against a plain white wall because the daylight was rapidly getting brighter when I shot the sunrise. The exposure was identical both with and without the filter.

What I Like and What Could Be Improved

The tests finally assured me that it is worth having a good quality filter attached to the camera, and the Urth Plus + filters are that. I could see no difference between using the filter and not.

They come nicely packaged in a metal tin and plastic-free, recyclable cardboard. There is a lens cloth included with the filter. Remember to look inside that box for the code to enter on a website, so Urth will plant an additional five trees on top of the five they grow when you buy the filter.

The filter itself comprises a solid yet slender metal mount. The German-made B270 Schott optical glass has a 30-layer coating.

I cannot think of anything other than positive things to say about the filter. If you shoot with professional standard glass and want to protect it, I recommend using this filter.

I could not say the same for any of the cheaper filters I tried. I must add that I didn’t test the more affordable filters on entry-level lenses. For those shooting on a budget or even using vintage glass, then would they be okay? This experiment didn’t prove that one way or another. Perhaps I will acquire an entry-level camera with a budget lens for testing that.  

I would like to hear about your experiences and see your tests with and without the filters you use.