If you get a good UV/Protection filter it will not degrade the image and in most cases will help.
Since I started in the industry in 1975 I have seen many new lens sales because the photographer was told not to put a clear filter on the lens and something happened. I agree, don't by garbage (Cheap). Most reputable photo specialty stores, like us, only carry quality filters.
The effect filters depend on what you are shooting. Circ Pol, ND, etc
