Table of Contents
Pentax-M SMC 50mm f/2
Summary
The SMC Pentax-M 50mm f/2 is a compact, manual-focus standard prime lens for Pentax K-mount 35mm and full-frame digital SLRs, produced from 1979 to 1985. It features a simple 5-element/5-group optical design, a 6-blade automatic diaphragm, and Pentax’s Super Multi-Coating (SMC) for improved contrast and flare resistance. With a maximum aperture of f/2, it offers decent low-light performance and shallow depth-of-field, while delivering solid sharpness and pleasing bokeh—especially when stopped down. The lens focuses down to 0.45m, uses a 49mm filter thread, and weighs just 160g in a compact 63 × 31mm all-metal barrel (early versions). Later production runs used plastic components from the A-series to reduce cost, resulting in a lighter 138g version with a slightly different aperture mechanism. Though often dismissed as a budget “kit lens,” it remains a surprisingly capable and affordable entry point into vintage Pentax glass.
Tech Specs
| Manufacturer | Pentax |
| Series | M 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 | 160g |
| Body Telescope | - |
| Body Material | - |
| Focus Drive | - |
| Iris Drive | - |
| Zoom Drive | - |
History
Country of Origin:
Release Date: 1979
Launch Price:
Design Revisions: