UV filters are often used to block extended UV rays on the front of a lens and as a longtime photographer I remember the days when a UV filter was a must to protect your lenses over the long term. ...or at least that was the theory. Unfortunately, much of this belief persists to this day, and while the benefits of a UV filter that provides protection is still a hotly debated topic, UV filters offer a very good benefit...they keep dirt/grime/fingerprints back from the front Main element of a camera lens. In wedding photography, it's not uncommon for a child/baby/drunk adult to reach out and try to touch your lens...in fact, attempts to do so can produce some of the most incredible shots if the timing is right. However, the expense and difficulty of cleaning a good, high-end lens is often many times more difficult than simply cleaning a lens cover on the front...which is where UV filters usually come in...they do the job good job direct contact with the actual lens. I've used many different types of filters over my decades of photography, and among these, UV filters are probably the ones that offer the widest range of quality. This is the first K&F filter I've used and I've been using it on a Sigma ART lens for a week. I'm happy to say that this filter is a nice mid to high end UV protector. Unlike so many cheaper UV filters, this one doesn't seem to introduce any easily noticeable color shift or image distortion with the image. While I'm sure if I start pixeling and comparing this UV filter to a $200+ filter I could probably find a few glitches here and there. In fact, this filter is half the price of many of the other upper mid-range filters. ... and let's be honest. The primary goal of a UV filter is protection. A decent UV filter shouldn't noticeably alter your images. In this respect, this product does exactly what it is supposed to. One thing the K&F excels at, however, is the case in which the filter is packaged. The case is a hard cylindrical case that is easy to twist open. However, the nicer aspect of this filter is the fact that the housing has a silicone ring with grooves in it that keeps the filter in place while it is in the housing. This is something many other manufacturers do NOT (including a large number of more high-end filter manufacturers). While yes, this is the first real experience with a K&F filter, for me...after looking at the attention to detail they have done, I am now in the market for a few others of theirs :)