B + W filters are the best choice!

Pro:
+ Multicoated
+ Nanocoating
+ XS version (particularly thin, but with a separate thread)
+ Good price / performance ratio

Cons:
- No complaints

Description:
For the protection of high-quality optics to UV filters are excellent. But if you save the filter, saving at the wrong end. Ultimately, always provides the filter represents an additional layer between the subject and lens and ideally should not adversely affect the image. For filters from B + W one must not fear this. They behave in the lens, such as if they were not there. Autofocus runs usual precision, without, as in some cheap filters there is irritation of the same. A big advantage of this filter is that it also ideally suited for wide-angle lenses. In contrast to the filters of normal version, these XS-Pro is significantly thinner. A major advantage of XS version is that yet an additional thread is on the filter and the possibility to screw another filter (risk of vignetting) or at least engage a lens cap securely. This possibility does not exist in the so-called Slim versions unfortunately. The storage of B + W is the usual high quality. Even with a fall of 1.5 meters, the plastic box was closed and the filter thanks to padding undamaged.

Conclusion:
Those who invest in high-quality optics and camera body, should not save the filter. The products from B + W can be purchased with a clear conscience and recommended. If you opt for a UV filter with 77mm, you should pay attention to the multi-coating (MRC) - it is well worth the small fee. The nano-coating is to me so far neither positive nor negative noticed. Because I care for my filter at regular intervals, has never set dirt with me and read easily removed even with the older generations without Nano.