| AF | Auto Focus |
| D | Distance Information. Adds distance information to the data transmitted to the camera via chip. Distinguished by the D or G after the lens designation |
| ED | Extra Low Dispersion Glass. Enable the production of lenses that offer superior sharpness and color correction by minimizing chromatic aberration. |
| N | Originally, the actual designation used for the first AI lenses; beginning in 2005 it now stands for Nano Crystal Coat, a special type of flare reduction coating applied to newer lenses. |
| SIC | Super Integrated Coating, a multi-layer flare reduction coating, usually applied to the more complex zoom lenses. |