JP S39-8148 Y1, sole example — Jiro Mukai
| 8 ELEMENTS / 4 GROUPS |
| DESIGN f = 35.05 mm |
| DESIGN F/1.4 |
| ALL SPHERICAL |
Unit focus: the whole optical unit moves forward on the non-revolving helicoid, so only the back focus changes, from 20.143 mm at infinity to 21.458 mm at Canon's 1 m minimum (object to film), a 1.315 mm extension. The patent prints the infinity state only; the near state is a paraxial calculation.
| Element | Type | Glass |
|---|---|---|
| L1 | Negative Meniscus | E-FD7 (HOYA catalog equivalent; production supplier unspecified) |
| L2 | Positive Meniscus | K-LaK9 (SUMITA catalog equivalent; production supplier unspecified) |
| L3 | Positive Meniscus | LAF2 (HOYA catalog equivalent; production supplier unspecified) |
| L4 | Negative Meniscus | SF2 (Schott catalog equivalent; production supplier unspecified) |
| L5 | Positive Meniscus | LAK6 (SUMITA catalog equivalent; production supplier unspecified) |
| L6 | Negative Meniscus | FF5 (HOYA catalog equivalent; production supplier unspecified) |
| L7 | Positive Meniscus | S-LAL8 (OHARA catalog equivalent; production supplier unspecified) |
| L8 | Biconvex Positive | K-LaK10 (SUMITA catalog equivalent; production supplier unspecified) |