Protects, neutral cleaning remains almost impossible.

The function very well:
The Hoya Protector Slim Filter now protects my Canon EF-S 10-22 lens. The image quality is not adversely affected. The colors and edge illumination in the picture remain unchanged, just as without a filter. The original front cover of the Canon lens fits continued, no longer quite so smoothly but it works.

The cleaning, a horror:
After extensive use, fingerprints, other Schlieren, fittings and dust on the filter were then sometime to recognize. The dust could be removed more easily, the streaks then required a wet cleaning. Only with a smooth slightly damp microfibre cloth (similar to leather) specially cleaned and dried cloth. The result was that now more bluish streaks were observed under light. Approximately 1 hr. And all sorts of different gentle cleanings later I wanted to throw away the filter, because the result was closer inspection under light still full of bluish streaks. Only a rather fluffy microfiber cloth (from Meguiars and actually for the car) brought the filters again the right Durchblick (not 100% sure but quite ok).

Conclusion:
Good and neutral protection for expensive lenses. In case of a cleansing is needed then but strong nerves.