If you need the actual technical top manual for repair (disassembling the focus ring or cleaning internal fungus), you cannot get it legally from Canon without being an authorized service center.
In professional lens documentation, there are usually three levels of manuals: canon yj18x9b4 manual top
This lens was a workhorse for SD (Standard Definition) and early HD cameras. Today, it is popular among indie filmmakers adapting B4 lenses to Micro Four Thirds or Blackmagic cameras due to its parfocal design (stays in focus while zooming) and fast aperture. If you need the actual technical top manual
While the lens has an auto iris connection, the manual suggests using the Manual Iris mode for critical exposure. The manual details how to override the auto aperture to prevent blowing out highlights in high-contrast scenes. While the lens has an auto iris connection,