Table of Contents
Pentax SMC 85mm f/1.8
Summary
The SMC Pentax 85mm f/1.8 is a manual-focus short telephoto prime introduced in 1975 as part of the original K-series lineup—the first generation of Pentax bayonet-mount lenses. It was produced until 1977, making it a relatively rare and sought-after optic today. Designed primarily for portraiture, it offers a fast f/1.8 aperture in a compact, all-metal body, and is widely praised for its optical clarity, smooth bokeh, and mechanical precision. Optically, the lens features a 6-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 85cm, yielding a 0.13× magnification ratio, and uses a 52mm filter thread. The lens weighs 331g, measures 64 × 56mm, 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 dedicated PH-R52 hood and hard case were originally supplied.
Tech Specs
| Manufacturer | Pentax |
| Series | K Series Prime |
| Model | SMC |
| Focal Length | 85mm |
| Max Aperture | f/1.8 |
| Min Aperture | f/22 |
| Format | Full-Frame |
| Image Circle | - |
| Minimum Focus | 85cm |
| Focus Rotation | ° |
| Iris Blades | 8 |
| Optical Design | 6/6 |
| Squeeze | none |
| Front Diameter | 64mm |
| Filter Thread | 52mm |
| Focus/Zoom Rod | none |
| Native Mount | Pentax K |
| Data Protocol | none |
| Length | 56mm |
| Weight | 331g |
| Body Telescope | - |
| Body Material | - |
| Focus Drive | - |
| Iris Drive | - |
| Zoom Drive | - |
History
Country of Origin:
Release Date: 1975
Launch Price:
Design Revisions: