You won't really notice much (or any) difference in your images. I use them on some lenses really to just protect the front element, especially if it's an expensive lens or I'm shooting near the ocean (to protect from the salt spray) or in the desert (to protect from blowing sand). If you decide to use one, get a quality coated filter like one made by Hoya or B&W. Adding another piece of glass in front of your lens just increases the chance of flare or reflections, but a good quality filter will minimize this while protecting the front element.