mechanical protection, not a "real" UV block

mechanical protection
Unfortunately, the Tiffen filters are described only very meager. This filter is the easiest Tiffen filter that protects the lens from damage and dirt mainly. Tiffen itself is no exact information, how much UV light is actually filtered. For those for whom this is important, possibly the Haze-1 (75% UV filter) or the haze-2 variant (100% UV filter) is interesting.

Topic UV
Of one reads that UV light "is bad for the sensor" and therefore a UV filter is useful - although the likes the odd scare for sale, but is simply wrong. UV filters have (in addition to the mechsnischen protection) their right to exist, if you photographed such as airplanes or birds in the sky (ideally 100% UV filter) or as mountain panoramas receives (75% variation) - the filter (so the theory goes) then takes the veil (chromatic aberration), which can be caused by UV radiation, from the images. At the same time a possible blue haze is reduced. For situations with bad weather offers various manufacturer nor the so-called Sky filter, thanks to lighter coloring allow warmer colors. None of these filters can filter out particles based haze or smog.

Conclusion
As today's SLR lenses already a significant proportion of UV radiation absorbing the mechanical protection of the lens is critical when making a purchase. If backlight image is captured, it is worthwhile, if necessary in a merhfach coated surface to invest (often multi-coated), reduces stray light. The price of the filter is measured by the quality of glass and filter thread in order. The theme UV is possibly of interest to the above scenarios, but negligible for the majority of buyers of this filter.