Focus
Manual
Mount
Large format flange mount
Notes
British equivalent of the Kodak Aero Ektar. Air Ministry marked, often with JHD stamp. 21 aperture blades produce extremely circular bokeh. Glass is not radioactive (unlike Aero Ektar). Some units made by other factories under Air Ministry contract. Used for portrait and large format photography via board mount.
Design
Heliar-type (5-element)
Format
Large format (covers 4x5 and 5x7)
Groups
3
Coating
Uncoated (front element)
Country
United Kingdom
Made By
J.H. Dallmeyer Ltd, London
Elements
5
Filter Thread
77mm
Production
1940s — WWII era
Stabilized
No
Max Aperture
f/2.9
Original Use
RAF aerial reconnaissance (Spitfire)
Weather Sealed
No
Aperture Blades
21
Focal Length Imperial
8 inches