Rainbow Research Optics Offers complete optical data design. They provide the following charts and information to help you determine your specific needs.  Lens TerminologyFocal Length Formulas for Singlet Lenses & MirrorsEffective Focal Length of Two Thin LensesF-Number (F/#)Numerical Aperture (N/A)Sagitta (Sag)Using Wedged WindowsSelecting a Prism, and Waveplates are all available through Rainbow Research Optics. For more information on these services visit www.rainbowoptics.com today!