Table of Contents
Pentax-A* SMC 300mm f/2.8 ED [IF]
Summary
The SMC Pentax-A* 300mm f/2.8 ED [IF] is a legendary manual-focus telephoto prime lens introduced in 1984 and produced until 1998, designed for K-mount 35mm and full-frame digital SLRs. It belongs to Pentax’s elite A* (A-Star) series and features an 8-element/8-group optical design with two ED (Extra-low Dispersion) elements and Internal Focusing (IF)—a rarity for its time. With a bright f/2.8 maximum aperture, it excels in low-light, sports, wildlife, and astrophotography, offering a shallow depth of field and creamy bokeh. The lens focuses down to 3 meters, delivers a 0.13× magnification, and includes a built-in sliding hood, tripod collar, and drop-in 43mm rear filter holder. It uses a massive 112 mm front filter, weighs a hefty 2,970g, and measures 133 × 236mm. A more compact alternative was offered in the A* 300mm F4.
Tech Specs
| Manufacturer | Pentax |
| Series | A* Series Prime |
| Model | SMC |
| Focal Length | 300mm |
| Max Aperture | f/2.8 ED [IF] |
| Min Aperture | f/32 |
| Format | Full-Frame |
| Image Circle | - |
| Minimum Focus | 300cm |
| Focus Rotation | ° |
| Iris Blades | 8 |
| Optical Design | 8/8 |
| Squeeze | none |
| Front Diameter | 133mm |
| Filter Thread | 112mm, 43mm rear |
| Focus/Zoom Rod | none |
| Native Mount | Pentax K |
| Data Protocol | none |
| Length | 236mm |
| Weight | 2970g |
| Body Telescope | - |
| Body Material | - |
| Focus Drive | - |
| Iris Drive | - |
| Zoom Drive | - |
History
Country of Origin:
Release Date: 1984
Launch Price:
Design Revisions: