alphabetical coding

:Some early lenses such asNikon and Olympus uses some alphabetical coding to illustratre the composition oftheir lenses. Fora na exmaple, each ZUIKO Lens is described with an alphabeticalprefix and suffix such as F . ZUlK0 AUTO-S, AUTO-T, etc. The prefix represents thenumber of elements in a lens in alphabetical order. For an instance, A =1element, B =2 elements, D =4 elements, and so forth. AUTO signifies automatic diaphragm. The suffix represents the type of lense: S :Standard, W =Wide Angle and T =Telephoto.While another example: