A few days ago, a double rainbow popped up outside my window after some brief rain showers. At the moment I have a pretty good view of the sky from my house on the second floor, and I oftentimes have my camera handy in case there is a gorgeous sunrise over the mountain. So I grabbed the setup I had (my FUJIFILM X-T3 with 100–400mm lens) and got a few photos. However, the zoom level was a bit too much, so I quickly switched to my 50–140mm to see if I could get more in the frame.
One thing I have attached to many of my lenses is a circular polarizer. And I just happened to have it on my 50–140mm lens at the time. So, out of curiosity, I rotated the filter to see what the results would be, and as I did so I saw the rainbow almost completely disappear! Turning it again revealed the rainbow, and makes it a little more pronounced than the photo without use of a filter. The second image below also shows what the rainbow looks like with the 100–400mm lens, without a circular polarizer attached.
Circular polarizers are extremely useful and I recommend that all photographers have at least one in their possession. In fact, Amazon has some of the “Amazon Basics” brand that I use regularly and they are very affordable. Plus, they make a huge impact on your photos, especially when working with wet surfaces, glare, and reflections.