When shopping for camera lens filters, the three most mutual you’ll find are Neutral Density (ND), Circular Polarizer (CPL), and Ultraviolet (UV).
What’due south the difference betwixt these filters? Which filters should you own? If you’re confused, don’t exist. This commodity will explain their differences.
What is an ND filter?
Neutral density filters are sunglasses for camera lenses. Meaning, they reduce the amount of light inbound the camera. In doing so, ND filters then help cameras utilize exposure settings that normally aren’t possible.
For case, when shooting photos of waterfalls or moving water, photographers typically tiresome their photographic camera’s shutter speed to effectually half-a-2nd. Achieving proper exposure at this speed can exist difficult because the camera cannot physically close the lens discontinuity any smaller and/or ISO has maxed out at 100.
ND filters help resolve these issues. By reducing light, the photographic camera may now exit its shutter open up for a half-second (or even so long y’all want) without overexposing the prototype.
When shopping for ND filters, there are a wide diverseness of sizes, densities, and qualitative differences. You also have a option between variable and solid, with the former providing a range of densities (eg, two-x stops) and the latter offering only one (eg, 3-stop, 6-stop, etc).
Variable neutral density filters provide fantastic flexibility and control — especially when shooting video — only they can sometimes cause unsightly cross-polarization effects (eg, turning blue skies dark blue, etc). Photographers generally avert variable NDs for this reason and instead use solid neutral density filters.
In my feel, variable neutral density filters are perfectly fine for general apply. But if you lot need to shoot something that counts, solid neutral density filters provide the best and most consistent results.
What is a CPL filter?
Circular polarizers are filters that removes glare and reflections from shiny surfaces. This reveals particular and texture in areas usually obscured by bright highlights.
They may sound similar to ND filters, simply CPLs are unlike. CPLs don’t darken an paradigm like NDs, but rather use polarized glass (invented by Edwin Land / Polaroid) to remove the wavelengths of light that cause reflections. This effect can be just exist achieved in-camera and is impossible to recreate later in Photoshop.
To use a CPL, you lot rotate the filter until reaching the appropriate angle betwixt your low-cal source (eg, the dominicus) and your subject. This is typically somewhere effectually 90 degrees. While turning the filter, proceed an middle on the preview paradigm on the back of your photographic camera to find the proper bending, and then make micro-adjustments effectually that angle to decide how strong the consequence should be.
What is a UV filter?
Ultraviolet filters are the simplest, to the lowest degree expensive filters because they don’t exercise much of anything. They may provide a niggling bit of ultraviolet light filtering, only by and large, you typically can’t tell the difference between a photo shot with or without a UV filter.
Most people buy UV filters to protect lenses. A clear UV filter screwed-onto the front of a camera lens protects the drinking glass from fingerprints, dust, scratches, or even breakage. If you’re investing in quality, professional lenses, adding UV filters to each lens is a smart thing to do.
Filter types and sizes
Filters are either circular or square. Circular filters screw-on to the forepart of lenses. Square filters are panes of glass held in front of a lens using specialized mounts. Circular filters are more mutual, though many landscape photographers prefer foursquare filters because they allow greater flexibility when combining filters and quick removal when not in use. For those simply starting out, circular is simpler and less expensive.
Circular filters are sold in different diameters, typically ranging from 37mm to 82mm or larger. This number
the focal length of your lens, simply rather its diameter. If you’re not certain what this number is, look for a number on the forepart or acme of the lens body. When in doubt, check the specifications for the lens from wherever you bought it from.
In general, it’s best to buy filters at larger diameters, and then use stride-upwardly rings to attach the same filters to lenses with smaller diameters. That style you’re not ownership the same filter at different sizes when you can just buy one and use it with every lens you own. If you buy both an ND and CPL at the same size, yous can easily stack them together (with the CPL out front) to both deadening downward the camera’s shutter speed and remove reflections.
What to read next
Check out my Best Neutral Density Filters of 2020 article for recommendations.