For the price, this is a decent circular polarizing filter for the amateur looking to use a polarizing filter. It includes a UV filter which I only consider extra.

Personally, I only recommend using UV filters when shooting film, as they generally don't improve the image quality of modern digital cameras and can only degrade it, if at all. I know a lot of people think of it as a protective layer for their expensive lenses, but I find that a cheap UV filter on your expensive lens is actually more likely to damage it. A case in point is that the threads on this filter are very sharp cut. You can feel and hear them crunch as you screw them in, and when they're tight, the sharp threads want them to snap. If the lens was bumped hard on the corner with the filter in this position, the UV filter could actually catch and damage the lens threads, requiring expert repairs to remove the filter and repair the lens. In my experience, just holding the lens hood provides far more protection than a UV filter possibly could.

With that out of the way, let's get to the content of this review, the CPL filter. For the price this will work perfectly. It darkens the sky when used properly in the right conditions and can help reduce glare and reflections. It doesn't appear to have any discernible color cast, which would be a problem. In fact, the only real problem I have with this filter is the mechanical function.

First, the threads are cut very sharply, as already mentioned with the UV filter. This isn't the end of the world, but it does couple with the fact that the rotating ring on the CPL filter is also very, very stiff and rotates quite a bit. To rotate it as required to accommodate current conditions you have to pull the filter onto your lens more tightly than I would like and with threads that sharp increases the risk of the threads snapping tightly onto your lens. It's possible for them to lock so tightly that it can be quite difficult to remove them from your lens. While $30 is a pretty good bargain for an otherwise pretty decent filter, it's no bargain when you run the risk of Costing you a lot of money to repair your expensive equipment. If you're using a cheap lens, this cheap filter should be fine. If you've spent a lot of money on an expensive lens, I wouldn't recommend cheaping out on the filters.

In the end I chose 4 stars because the glass is of a pretty good quality and if you are aware of the limitations it is safe to use as long as you don't over tighten it. It's just a little less practical. But otherwise it works fine.