Table of Contents
Pentax-A SMC 28mm f/2.8
Summary
The SMC Pentax-A 28mm f/2.8 is a compact, manual-focus wide-angle prime introduced in 1984 and produced until 1988, designed for full-frame K-mount film cameras. It shares the same optical formula as the second version of the Pentax-M 28/2.8 but adds an “A” setting on the aperture ring, enabling full program and shutter-priority automation on compatible Pentax bodies. Optically, it features a 7-element/7-group design, Super Multi-Coating (SMC), and a 5-blade automatic diaphragm. It delivers a 75° diagonal field of view on full-frame (or ~55° on APS-C), focuses down to 30cm, and offers 0.13× magnification. The lens uses a 49mm filter thread, weighs just 170g, and measures 63 × 36.5mm. It was originally paired with the PH-S49 hood and HA-90B hard case, though these were often sold separately.
Tech Specs
| Manufacturer | Pentax |
| Series | A Series Prime |
| Model | SMC |
| Focal Length | 28mm |
| Max Aperture | f/2.8 |
| Min Aperture | f/22 |
| Format | Full-Frame |
| Image Circle | - |
| Minimum Focus | 30cm |
| Focus Rotation | ° |
| Iris Blades | 5 |
| Optical Design | 7/7 |
| Squeeze | none |
| Front Diameter | 63mm |
| Filter Thread | 49mm |
| Focus/Zoom Rod | none |
| Native Mount | Pentax K |
| Data Protocol | none |
| Length | 36.5mm |
| Weight | 170g |
| Body Telescope | - |
| Body Material | - |
| Focus Drive | - |
| Iris Drive | - |
| Zoom Drive | - |
History
Country of Origin:
Release Date: 1984
Launch Price:
Design Revisions: