We are often asked what the letter following the word "Nikkor" on early pre-Ai lenses means. Each Nikkor lens has certain markings indicating the optical design. These letters were codes indicating the number of elements in each lens. The letters are derived from Latin and Greek words denoting numbers:
U = Uns = 1 element
B = Bini = 2 elements
T = Tres = 3 elements
Q = Quatuor = 4 elements
P = Pente = 5 elements
H = Hex = 6 elements
S = Septem = 7 elements
O = Octo = 8 elements
N = Novem = 9 elementsD = Dece = 10 elements

For example the 50mm f/2 Nikkor S would indicate a 7 element lens. Later the letter 'C' began to appear, following the code letter for the number for elements: e.g. 50mm f/1.4 Nikkor SC. The C-type Nikkors indicate that some or all of their glass elements are multi-coated. There were slight cosmetic changes that also differentiate the C-type lenses, which have a black finish to their filter ring.

About Grays of Westminster Glossary Page
All subjects have their own nomenclature and photography is no exception. In common with other manufacturers, Nikon use abbreviations to describe their products, which can sometimes cause confusion to someone new to the system. As a special service to Nikon users and enthusiasts, and in an effort to clarify and make defining any terminology that has been used simpler, we are offering the Grays of Westminster Glossary Page as a brand new service.

If you do not see the definition or answer to a question you are seeking, please feel free to email us at glossary@graysofwestminster.co.uk with your request and we will do our best to answer you.