Table of Contents
Pentax-M SMC 35-70mm f/2.8
Summary
The SMC Pentax-AF 35-70mm f/2.8 is a historically significant lens introduced in 1981 as Pentax’s first autofocus lens, designed exclusively for the Pentax ME-F—the world’s first TTL autofocus SLR. It features a constant f/2.8 aperture, a rarity at the time, and was built with an in-lens AF motor powered by four AAA batteries. On any camera other than the ME-F, it functions as a manual-focus lens, behaving much like an M-series zoom with no electronic aperture control. Optically, it employs a 7-element, 7-group design with Super Multi-Coating (SMC) and an 8-blade automatic diaphragm, stopping down to f/22. It focuses as close as 1.2 meters, uses a 58mm filter thread, and weighs 580g, measuring 73 × 77mm. The lens lacks internal focusing, quick-shift, or an “A” setting on the aperture ring, so it requires stop-down metering on modern bodies. It was typically bundled with a RH-60 slip-on hood and a dedicated hard case.
Tech Specs
| Manufacturer | Pentax |
| Series | M Series Zoom |
| Model | SMC |
| Focal Length | 35-70mm |
| Max Aperture | f/2.8 |
| Min Aperture | f/22 |
| Format | Full-Frame |
| Image Circle | - |
| Minimum Focus | 120cm |
| Focus Rotation | ° |
| Iris Blades | 8 |
| Optical Design | 7/7 |
| Squeeze | none |
| Front Diameter | 73mm |
| Filter Thread | 58mm |
| Focus/Zoom Rod | none |
| Native Mount | Pentax K |
| Data Protocol | none |
| Length | 77mm |
| Weight | 580g |
| Body Telescope | - |
| Body Material | - |
| Focus Drive | - |
| Iris Drive | - |
| Zoom Drive | - |
History
Country of Origin:
Release Date: 1981
Launch Price:
Design Revisions: