Table of Contents
Pentax-A SMC 16mm f/2.8 Fish-Eye
Summary
The SMC Pentax-A 16mm f/2.8 Fish-Eye is a rare and distinctive ultra-wide-angle prime introduced in 1985 and produced until 2004, designed for full-frame K-mount film cameras. It was the final evolution of Pentax’s diagonal fisheye primes, replacing the earlier K 17mm f/4 and offering a full 180° diagonal field of view with a faster f/2.8 aperture—making it a standout in the A-series lineup. Optically, it features a 9-element - 7-group design with Super Multi-Coating (SMC) and a 6-blade automatic diaphragm. The lens stops down to f/22, focuses as close as 20cm, and delivers 0.15× magnification. It lacks a front filter thread due to its bulbous front element, but includes three built-in filters—Skylight, Yellow (Y2), and Orange (O2)—selectable via a rotating dial. There’s also a rear gelatin filter holder for additional creative control. It weighs 320g, measures 65 × 56mm, and includes a built-in metal hood and dedicated slip-on cap. The “A” setting on the aperture ring allows for full program and shutter-priority automation on compatible bodies.
Tech Specs
| Manufacturer | Pentax |
| Series | A Series Fish-Eye |
| Model | SMC |
| Focal Length | 16mm |
| Max Aperture | f/2.8 |
| Min Aperture | f/22 |
| Format | Full-Frame |
| Image Circle | - |
| Minimum Focus | 20cm |
| Focus Rotation | ° |
| Iris Blades | 6 |
| Optical Design | 9/7 |
| Squeeze | none |
| Front Diameter | 65mm |
| Filter Thread | none (built in filter wheel) |
| Focus/Zoom Rod | none |
| Native Mount | Pentax K |
| Data Protocol | none |
| Length | 56mm |
| Weight | 320g |
| Body Telescope | - |
| Body Material | - |
| Focus Drive | - |
| Iris Drive | - |
| Zoom Drive | - |
History
Country of Origin:
Release Date: 1985
Launch Price:
Design Revisions: