YouTuber Joshua Cripps, through his Professional Photography Tips channel, recently released a great video detailing exactly what CPL filters are, when to use them, and how to do it. It’s a great crash course for anyone new to photography or filters that is looking to get a quick education on how to take advantage of these incredible photographic tools.
As shown in the video, Circular Polarizing filters are great landscape and outdoor photography where reflections can impact an image. Some great examples of situations like this would be shooting a waterfall, creek, or lake. The reflections from the water can cause issues in an image, so by utilizing a CPL filter, which filters out scattered light, you are able to cut through those reflections and see the detail behind it. In the situations mentioned above, it would cause rocks around the waterfall to have more detail, allowing you to see the creek or lake bed under the surface of the water, rather than a reflection of the sky you would normally get without the filter.
CPL filters are not all that expensive either, and depending on the size of your lens you can pick up a decent-quality filter — not the best, but not the worst either — for less than $50, easy. That may seem expensive for what is essentially a piece of glass you screw into the front of your lens but as the video above shows you, the results speak for themselves.