Table of Contents
Pentax-M SMC 100mm f/2.8
Summary
The SMC Pentax-M 100mm f/2.8 is a compact, manual-focus short telephoto prime introduced in 1977 and produced until 1984, designed for full-frame K-mount film cameras. It was part of the M-series, known for its portability and solid construction, and served as a non-macro alternative to the longer and heavier 100mm f/4 Macro. Optically, it features a 5-element/5-group design, Super Multi-Coating (SMC), and a 6-blade automatic diaphragm. It delivers a 24° diagonal field of view on full-frame (or ~16° on APS-C), focuses down to 1 meter, and provides 0.13× magnification. The lens uses a 49mm filter thread, weighs just 225g, and measures 62.5 × 55.7mm. It lacks an “A” setting on the aperture ring, so it’s best used in manual or aperture-priority modes on modern digital bodies. A clip-on hood and dedicated hard case were originally included.
Tech Specs
| Manufacturer | Pentax |
| Series | M Series Prime |
| Model | SMC |
| Focal Length | 100mm |
| Max Aperture | f/2.8 |
| Min Aperture | f/22 |
| Format | Full-Frame |
| Image Circle | - |
| Minimum Focus | 100cm |
| Focus Rotation | ° |
| Iris Blades | 6 |
| Optical Design | 5/5 |
| Squeeze | none |
| Front Diameter | 62.5mm |
| Filter Thread | 49mm |
| Focus/Zoom Rod | none |
| Native Mount | Pentax K |
| Data Protocol | none |
| Length | 55.7mm |
| Weight | 225g |
| Body Telescope | - |
| Body Material | - |
| Focus Drive | - |
| Iris Drive | - |
| Zoom Drive | - |
History
Country of Origin:
Release Date: 1977
Launch Price:
Design Revisions: