Table of Contents
Pentax-A SMC 50mm f/1.7
Summary
The SMC Pentax-A 50mm f/1.7 is a compact, fast standard prime lens for Pentax K-mount 35mm and full-frame digital SLRs, produced from 1984 to 1989. It features a 6-element/5-group optical design, a 6-blade automatic diaphragm, and Pentax’s Super Multi-Coating (SMC) for improved contrast, color fidelity, and flare resistance. With a bright f/1.7 aperture, it excels in low-light conditions and offers pleasing background blur—especially from f/2.8 to f/5.6. The lens focuses down to 0.45m, delivers a 0.15× magnification, and uses a 49mm filter thread. It weighs just 165g and measures 63 × 31mm, housed in a compact polycarbonate-and-metal barrel. The standout feature is its “A” setting on the aperture ring, enabling full Program, Shutter-priority, and Aperture-priority modes on compatible Pentax film and digital bodies. This makes it one of the most versatile manual-focus 50 mm lenses in the Pentax lineup.
Tech Specs
| Manufacturer | Pentax |
| Series | A Series Prime |
| Model | SMC |
| Focal Length | 50mm |
| Max Aperture | f/1.7 |
| Min Aperture | f/22 |
| Format | Full-Frame |
| Image Circle | - |
| Minimum Focus | 45cm |
| Focus Rotation | ° |
| Iris Blades | 6 |
| Optical Design | 6/5 |
| Squeeze | none |
| Front Diameter | 63mm |
| Filter Thread | 49mm |
| Focus/Zoom Rod | none |
| Native Mount | Pentax K |
| Data Protocol | none |
| Length | 31mm |
| Weight | 165g |
| Body Telescope | - |
| Body Material | - |
| Focus Drive | - |
| Iris Drive | - |
| Zoom Drive | - |
History
Country of Origin:
Release Date: 1984
Launch Price:
Design Revisions: