Table of Contents
Pentax-A 645 SMC 35mm f/3.5
Summary
The SMC Pentax-A 645 35mm f/3.5 is a manual-focus ultra-wide prime introduced in 1986 for the Pentax 645 medium format system, offering a field of view equivalent to roughly 24mm on full-frame. It was the widest prime available for the original 645 lineup and remains a favorite among landscape, architecture, and street photographers for its expansive coverage and classic rendering. Though later replaced by the autofocus FA and HD D FA versions, the A-series model is still prized for its mechanical precision, compact build, and optical character. Optically, it features a 9-element, 8-group design with Super Multi-Coating (SMC) and an 8-blade automatic diaphragm, stopping down to f/22. The lens focuses as close as 30 cm, delivering a 0.25× magnification ratio, and uses a 77mm filter thread. It weighs 470g, measures 80 × 67mm, and includes a manual aperture ring with an “A” setting, enabling full automation on compatible bodies. There’s no internal focusing. A RH-RB screw-in hood and S80-120 soft case were typically bundled.
Tech Specs
| Manufacturer | Pentax |
| Series | Pentax-A |
| Model | 645 SMC |
| Focal Length | 35mm |
| Max Aperture | f/3.5 |
| Min Aperture | f/22 |
| Format | 645 film |
| Image Circle | - |
| Minimum Focus | 30cm |
| Focus Rotation | ° |
| Iris Blades | 8 |
| Optical Design | 9/8 |
| Squeeze | none |
| Front Diameter | 80mm |
| Filter Thread | 77mm |
| Focus/Zoom Rod | none |
| Native Mount | Pentax 645 |
| Data Protocol | none |
| Length | 67mm |
| Weight | 470g |
| Body Telescope | - |
| Body Material | - |
| Focus Drive | - |
| Iris Drive | - |
| Zoom Drive | - |
History
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