Table of Contents
Pentax-M SMC 100mm f/4 Macro
Summary
The SMC Pentax-M 100mm f/4 Macro is a compact, manual-focus macro lens introduced in 1977 and produced until 1984, designed for full-frame K-mount film cameras. It delivers 1:2 magnification natively and can reach 1:1 with extension tubes, making it a versatile tool for close-up, product, and nature photography. Optically, it features a 5-element/3-group design, Super Multi-Coating (SMC), and a 6-blade automatic diaphragm. It stops down to f/32, focuses as close as 45cm, and provides a 0.5× reproduction ratio. The lens uses a 49mm filter thread, weighs 355g, and measures 64.6 × 77.5mm. 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 dedicated hard case was included, and while a PH-R49 hood fits, it’s rarely needed thanks to the deeply recessed front element.
Tech Specs
| Manufacturer | Pentax |
| Series | M Series Macro |
| Model | SMC |
| Focal Length | 100mm |
| Max Aperture | f/4 |
| Min Aperture | f/32 |
| Format | Full-Frame |
| Image Circle | - |
| Minimum Focus | 45cm |
| Focus Rotation | ° |
| Iris Blades | 6 |
| Optical Design | 5/3 |
| Squeeze | none |
| Front Diameter | 64.6mm |
| Filter Thread | 49mm |
| Focus/Zoom Rod | none |
| Native Mount | Pentax K |
| Data Protocol | none |
| Length | 77.5mm |
| Weight | 355g |
| Body Telescope | - |
| Body Material | - |
| Focus Drive | - |
| Iris Drive | - |
| Zoom Drive | - |
History
Country of Origin:
Release Date: 1977
Launch Price:
Design Revisions: