K 8.4/2.8 Bird’s-Eye

General Description
A circular fish-eye lens.
| Product Information | |
|---|---|
| Exact Name | smc PENTAX BIRDS-EYE 1:2.8 8.4 mm | 
| Color | black | 
| Year of Introduction | Photokina 1982 | 
Technical Specifications
| Optics | |
|---|---|
| Optical Formula | 10 elements in 7 groups | 
| Aperture Range | f/2.8 ~ f/unknown | 
| Number of Aperture Blades | unknown | 
| Minimum Focusing Distance | lens has no focusing ring | 
| Maximum Magnification | depends on the lens-to-subject distance | 
| Special Features | bird’s-eye lens | 
| Mechanics | |
| Front-Filter Thread | no | 
| Gelatine-Filter Holder | yes | 
| Maximum Diameter | unknown | 
| Length | unknown | 
| Weight | unknown | 
| Special Features | manual diaphragm | 
| Accessories | |
| Cap | unknown | 
| Fitting Hood(s) | unknown | 
| Fitting Case(s) | unknown |