Table of Contents
Pentax SMC 50mm f/4 Macro
Summary
The SMC Pentax 50mm f/4 Macro (K version) is a vintage macro lens introduced in the mid-1970s as Pentax’s first K-mount close-focusing prime. Built around a classic Tessar-type 4-element, 3-group optical formula, it delivers exceptional flat-field sharpness and minimal distortion, making it ideal for product photography, botanical subjects, and document reproduction. While slower than typical 50mm lenses, its optical precision and mechanical finesse give it enduring appeal among macro enthusiasts and collectors. The lens features early SMC multicoating, a 5-blade diaphragm stopping down to f/32, and focuses down to 23cm for 0.5× magnification. It uses a 52mm filter thread, weighs 241g, and measures 63 × 54mm. The front element is deeply recessed, effectively acting as its own lens hood, and the engraved barrel markings include reproduction ratios for easy macro reference. There is no “A” setting on the aperture ring, so stop-down metering is required on digital bodies. The lens is fully manual with a long, damped focus throw and a solid all-metal build, giving it a tactile confidence in use.
Tech Specs
| Manufacturer | Pentax |
| Series | K Series Macro |
| Model | SMC |
| Focal Length | 50mm |
| Max Aperture | f/4 |
| Min Aperture | f/32 |
| Format | Full-Frame |
| Image Circle | - |
| Minimum Focus | 23cm |
| Focus Rotation | ° |
| Iris Blades | 5 |
| Optical Design | 4/3 |
| Squeeze | none |
| Front Diameter | 63mm |
| Filter Thread | 52mm |
| Focus/Zoom Rod | none |
| Native Mount | Pentax K |
| Data Protocol | none |
| Length | 54mm |
| Weight | 241g |
| Body Telescope | - |
| Body Material | - |
| Focus Drive | - |
| Iris Drive | - |
| Zoom Drive | - |
History
Country of Origin:
Release Date: 1975
Launch Price:
Design Revisions: