Your camera won't allow you to develop clear, crisp photos if your camera lens is damaged or dirty. You can protect your thousand dollar lens with a $20 filter if you use a UV or haze filter. These thin glass filters are designed to screw onto the end of your camera lens and you can just leave them on to protect your lens. UV filters can help protect your lenses from dust, moisture and scratches. If your lens is damaged it could cost you quite a bit to repair or replace it. The filters can also give you added benefits of correction for Ultraviolet light which can show on your film as a bluish cast and can sometimes distort distant details. UV filters let you correct for the UV effect to varying degrees. They are also useful if you are shooting mountain and marine scenes, as the haze could affect the color and clarity of the photos. UV filters can be bought for about $20.