Collecting Military Binoculars
Swift Audubon 8.5 x 44 model 820ED
No: 112464
The Japanese Tamron company’s optics specialists were specifically commissioned by the Swift company to design the first Swift Audubon binoculars. The design was based on the ornithological market research. Currently sold models are already the third generation of this series.
The porro prismatic Swift Audubon ED 8.5x44 model includes low dispersion ED glass in the objective lens which task is to fight against the chromatic and spherical aberration and raising the contrast level by 5-10% compared to normal binoculars.
Apart from the objective lens we deal here with Porro system prisms and five-lens eyepieces, which ensure one of the widest field of view in this class.
Everything is closed in a waterproof and nitrogen-filled magnesium barrel padded with high quality rubber. All air-to-glass surfaces were covered by antireflection coatings.