Nikon Series E 50mm built from 1979 to 1985. This is one of my favorite lenses, it is compact, light, and fully manual. Focusing a lens yourself takes a bit of practice but you will be glad to have that skill because even the best new autofocus systems can struggle to do its job in some situations. The aperture opens to f1.8 which is great for letting in some extra light when needed and creating a soft blurry background for portraits. You can usually find them for around $60-$80 in excellent used condition and they were very popular during the time they were made so it is not hard to find.