Instruction manual in PDF format

Abbreviations
FDThe lens is designed for Canon 35mm film SLR cameras with the Canon FD mount
Optical design
Magnification factor2x
Maximum format35mm full frame
MountCanon FD
Lens construction6 elements in 4 groups
Physical characteristics
Weight210g
Maximum diameter x Length⌀64×35.2mm

Sources of data

  1. https://lens-db.com/tc/canon-extender-fd-2x-a/