Table of Contents
Pentax SMC 55mm f/1.8
Summary
The SMC Pentax 55mm f/1.8 is a manual-focus standard prime lens introduced in 1975 as part of the original K-series lineup—Pentax’s first bayonet-mount lenses following the M42 era. It features a 6-element/5-group optical design, a 6-blade automatic diaphragm, and Super Multi-Coating (SMC) for enhanced contrast and flare resistance. With a fast f/1.8 aperture, it excels in low-light shooting and offers pleasing background blur, especially for portraits and general-purpose photography. The lens focuses down to 0.45m, delivers a 0.17× magnification, and uses a 52mm filter thread. It weighs 221g, measures 63 × 39mm, and lacks an “A” setting on the aperture ring—making it fully compatible with manual and aperture-priority modes on Pentax DSLRs.
Tech Specs
| Manufacturer | Pentax |
| Series | K Series Prime |
| Model | SMC |
| Focal Length | 55mm |
| Max Aperture | f/1.8 |
| 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 | 52mm |
| Focus/Zoom Rod | none |
| Native Mount | Pentax K |
| Data Protocol | none |
| Length | 39mm |
| Weight | 221g |
| Body Telescope | - |
| Body Material | - |
| Focus Drive | - |
| Iris Drive | - |
| Zoom Drive | - |
History
Country of Origin:
Release Date: 1975
Launch Price:
Design Revisions: