Speaking from the perspective of a photographer I can tell you that ANY aberration in the optics of a camera will have a detrimental effect on the quality of the image recorded. As light is refracted through a lens the scattering of the spectrum will cause unexpected and, often, unwanted lighting effects in the finished image. Best of all worlds... keep your lens (and protective outer casing) protected until ready for use, then remove any outer covering from the camera lens before taking photos. Then cover again until the next use.
Happy photo hunting.