Any lens with a focal length greater than a “normal lens”. For 35mm work, the telephoto range extends from about 85mm to as long as a lens can be.
Different to the Wide-Angle Lens which creates the illusion of a greater distance (and therefore distorts the subject) the effect of a telephoto lens is a magnification of your subject. The bigger the Focal length, the higher the magnifaction of the subject will be.
none.