Lens Filters

How do I know what size filter I need?

The size of filter you need is generally determined by the filter thread size that is indicated around the front element of the lens. There are a wide range of different sizes including 37, 39, 40, 40.5, 43, 46, 49, 52, 55, 58, 60, 62, 67, 72, 77, 82, 86, 95. The size is shown using the diameter symbol: ø, followed by the figure. So, for example if it’s a 52mm filter thread, it will be shown as ø52, or if it’s a 77mm, it’ll be shown as ø77.

However, there are some lenses that either do not have a filter thread marker or a thread at all e.g. some fisheye or long telephoto lenses! These require different types of filters and/or different methods of attaching the filters such as a filter holder system. For this example, you’ll often use square or rectangular plate filters that slot into the holder systems - These are particularly popular with landscape photographers as you can easily stack multiple filters to capture dramatic scenes.

How to use camera lens filters?

There are a couple of methods to use camera lens filters but mainly you’ll come across screw-on filters that are attached to the front element of your lens. There are filter mount systems that use square or rectangle filter plates that are locked in place. Drop-in filters are used on large telephoto lenses that have specifically designed filter slots. Finally, Matte Boxes are primarily used on video projects; they have a large hood with a space for a filter without causing vignetting.

Do you need a UV filter for camera lenses?

You don’t have to have a filter but it is a good idea to have one. If not for the UV protection, a UV filter offers protection from dust, debris, moisture, scratches and the occasional fingerprint on the front element on your lens.

How to clean a camera lens filter?

You can clean a camera lens filter with a microfibre cloth and an air blower. You also can store your filters in a protective case that will keep them clean whilst not in use.

Go cheap or go expensive?

There are all sorts of filters, all with vastly different price points. The difference in price comes down to the quality of the materials and the anti-reflective and colour lens coatings used. More expensive filters are often made from high quality glass that is both optically purer and thinner than others on the market. Lower quality resin filters (when professionally tested) will often provide the desired lens effect but will negatively impact image quality e.g. slight colour casts across images.

This is the same for lens coatings - a lower quality coating results in a poorer image. Other factors play a part such as the outer ring of the filter or holder; whether it is aluminium or brass. The decision comes down to you as the practitioner, the gear you’re using and the intended audience.