Table of Contents
Pentax-A SMC 50mm f/2
Summary
The SMC Pentax-A 50mm f/2 is a compact, manual-focus standard prime lens introduced in 1985 and produced until 1998, designed for full-frame K-mount film cameras and fully compatible with modern Pentax DSLRs. It was marketed as a budget kit lens during the rise of auto-exposure bodies, offering a lower-cost alternative to the faster f/1.7 and f/1.4 options. Optically, it features a 5-element/5-group design, a 6-blade automatic diaphragm, and Super Multi-Coating (SMC) for improved contrast and flare resistance. The lens focuses down to 45cm, delivers 0.15× magnification, and uses a 49mm filter thread. It weighs just 145g, measures 63 × 31mm, and includes an “A” setting on the aperture ring, enabling full program and shutter-priority modes on compatible Pentax bodies.
Tech Specs
| Manufacturer | Pentax |
| Series | A Series Prime |
| Model | SMC |
| Focal Length | 50mm |
| Max Aperture | f/2 |
| Min Aperture | f/22 |
| Format | Full-Frame |
| Image Circle | - |
| Minimum Focus | 45cm |
| Focus Rotation | ° |
| Iris Blades | 6 |
| Optical Design | 5/5 |
| Squeeze | none |
| Front Diameter | 63mm |
| Filter Thread | 49mm |
| Focus/Zoom Rod | none |
| Native Mount | Pentax K |
| Data Protocol | none |
| Length | 31mm |
| Weight | 145g |
| Body Telescope | - |
| Body Material | - |
| Focus Drive | - |
| Iris Drive | - |
| Zoom Drive | - |
History
Country of Origin:
Release Date: 1985
Launch Price:
Design Revisions: