K version
Ai version showing different rear construction
| Version | Serial no | Date | Screws | Engraving | Notes |
|---|---|---|---|---|---|
| K,Ai | 174011 < 174048 � 186813 > | Sep 75 - Jun 77 | 5+ | LMIJ | Some Ai lenses found in this range. |
| Ai | < 187322 � 190085 > | Jun 77 - | 5+ | LMIJ | From 187xxx all are Ai. |
| Ai | 210001 < 210060 � 213654 > | - Aug 78 | 5+ | LMIJ | New serial no for Ai series. |