Table of Contents
Pentax-A 645 SMC 150mm f/3.5
Summary
The SMC Pentax-A 645 150mm f/3.5 is a manual-focus short telephoto prime introduced in the mid-1980s for the Pentax 645 medium format system. With a 35mm equivalent focal length of approximately 90-96mm, it was designed as a compact, affordable portrait and landscape lens—slotting neatly between the 120mm macro and the longer 200mm telephoto options. Optically, it features a 4-element - 4-group design with Super Multi-Coating (SMC) and an 8-blade automatic diaphragm. The lens stops down to f/32, focuses as close as 1.4 meters, and delivers a 0.15× magnification ratio. It uses a 58mm filter thread, weighs around 435g, and measures 74 × 71.5mm. It includes a built-in sliding metal hood with a rubber bumper, a manual aperture ring with “A” setting, and was typically sold with the S80-120 soft case. There’s no internal focusing or weather sealing, but the front element does not rotate—making it friendly for polarizer use.
Tech Specs
| Manufacturer | Pentax |
| Series | Pentax-A |
| Model | 645 SMC |
| Focal Length | 150mm |
| Max Aperture | f/3.5 |
| Min Aperture | f/32 |
| Format | 645 film |
| Image Circle | - |
| Minimum Focus | 140cm |
| Focus Rotation | ° |
| Iris Blades | 8 |
| Optical Design | 4/4 |
| Squeeze | none |
| Front Diameter | 74mm |
| Filter Thread | 58mm |
| Focus/Zoom Rod | none |
| Native Mount | Pentax 645 |
| Data Protocol | none |
| Length | 71.5mm |
| Weight | 435g |
| Body Telescope | - |
| Body Material | - |
| Focus Drive | - |
| Iris Drive | - |
| Zoom Drive | - |
History
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