Table of Contents
Pentax-M SMC 50mm f/1.4
Summary
The SMC Pentax-M 50mm f/1.4 is a classic manual-focus standard prime introduced in 1977 as part of Pentax’s compact M-series for the K-mount system. It replaced the earlier K-series version and remained in production until 1984, offering a fast aperture in a smaller, lighter package tailored to match the sleek ME and MX bodies of the era. With its f/1.4 maximum aperture, it was the flagship standard lens of the M-series lineup, prized for its low-light capability and shallow depth of field. Optically, the lens features a 7-element, 6-group design with Super Multi-Coating (SMC) and an 8-blade automatic diaphragm, stopping down to f/22. It focuses as close as 45cm, delivers a 0.15× magnification ratio, and uses a 49mm filter thread. The lens weighs 235g, measures 63 × 37mm, and includes a manual aperture ring with no “A” setting—so metering on modern digital bodies requires stop-down operation. There’s no internal focusing, and the front element rotates during focusing, which complicates polarizer use. A variety of hoods were compatible, including the PH-S49 and screw-in rubber types.
Tech Specs
| Manufacturer | Pentax |
| Series | M Series Prime |
| Model | SMC |
| Focal Length | 50mm |
| Max Aperture | f/1.4 |
| Min Aperture | f/22 |
| Format | Full-Frame |
| Image Circle | - |
| Minimum Focus | 45cm |
| Focus Rotation | ° |
| Iris Blades | 8 |
| Optical Design | 7/6 |
| Squeeze | none |
| Front Diameter | 63mm |
| Filter Thread | 49mm |
| Focus/Zoom Rod | none |
| Native Mount | Pentax K |
| Data Protocol | none |
| Length | 37mm |
| Weight | 235g |
| Body Telescope | - |
| Body Material | - |
| Focus Drive | - |
| Iris Drive | - |
| Zoom Drive | - |
History
Country of Origin:
Release Date: 1977
Launch Price:
Design Revisions: