A lens that is thinner in the center than at the edges. Some examples are fun house mirrors, make-up/shaving mirror, satellite dish.
a lens that is thicker in the middle than at the edges and bends light rays towards a focal point. Some examples are eyeglasses and magnifying lens.
Has only one fixed objective lens. (You cannot switch lenses.) Developed by Leeuwenhoek
Has at least 2 objective lenses. Developed by Hooke.
Has zero objective lens. Very expensive but provides a very, clear image
Formula for Total Magnification
eypiece x objective lens = total magnification