Spherical Lenses

Summary

• A lens is any piece of transparent material with at least one curved surface.
• There are two types of lenses.
  • A converging lens is any piece of transparent material that will converge parallel rays of light down to a point.
    • Converging lenses are thicker in the middle than at the edges.
  • A diverging lens is any piece of transparent material that will cause parallel rays of light to appear to diverge from a point.
    • Diverging lenses are thicker at the edges than in the middle.
• The focal point or focus isthe point which rays of light initially parallel converge towards after emerging from a converging lens or diverge from after emerging from a diverging lens.
  • In diagrams, the focus is indicated with the symbol F.
• The magnification formula.

  M =  hi  =  di ho do

• The thin lens formula (physicist form).

  1  =  1  +  1 f do di

• The thin lens formula (optometrist form).

  P = Vo + Vi