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Like most potential purchasers I acquired this filter to protect the front element of a lens with a 72mm thread. Swayed by the argument that you should not spend hundreds of pounds on a lens only to put a cheap filter in front of it, I chose the "pro" version, which is manufactured from multicoated optical glass. Though theoretically UV filters reduce haze in landscapes, I find it makes no discernable difference in the real world. With or without the filter the final image looks the same. The metal filter ring is well engineered, but it is difficult to align the threads properly when fitting a filter this size. The filter ring has a second thread so you can stack filters if you wish.
If you own several lenses, it may be worth buying a filter for the largest and using step-down rings for lenses of smaller diameter, however I have not adopted this approach as the lens hoods on my smaller lenses will not fit over a larger filter. With respect to optical quality, I cannot detect any loss of sharpness with this filter in situ, and so can see no benefit in using a filter costing more than this one, though a professional photographer of my acquaintance uses B + W UV filters on his lenses so obviously he disagrees. Perhaps with a really good camera system you would notice a difference, but you would really have to look closely. I have found that the lens is more prone to flare at wide angle with this filter in place, unless I use the lens hood.
Whether it is really necessary to protect the front element with a filter at all is another matter. Personally, I like the reassurance, but you would probably do just as well to leave the lens cap on when not actually taking pictures.