Tout à fait: joint + multicouche: http://luminous-landscape.com/reviews/c-ext.shtml
In 2001 Canon updated both their EF 1.4X and 2X Extenders. Both now have the designation II after their model numbers. In both cases Canon added rubber weather sealing on the mount, designed to mate with the seals on their then new line of Image Stabilized super-telephoto lenses. They claim to have added new anti-reflection coating to both units, but also to have completely redesigned the 2X.

Donc le 1.4x a la même bonne formule optique que le v I