The most essential filter you can own for protecting your digital camera lens against dust, moisture, fingerprints, scratches and damage. This filter can be kept on your camera lens at all times.

I tried to research which filters have the best light transmission and I found this article that measured multiple filters. Hoya came back with great results.

https://www.lensrentals.com/blog/2017/06/the-comprehensive-ranking-of-the-major-uv-filters-on-the-market/