全时手动的概念是伴随着佳能EF系列自动聚焦镜头的诞生而出现的。佳能EOS系列自动聚焦相机镜头与机身全电子耦合，采用镜头内置动力源驱动聚焦，从而为这一技术的成功运用提供了可能。顾名思义，全时手动就是说全部的时间（AF或非AF状态）都可以手动（聚焦），严格讲应是全时机 The all-time manual concept came along with the birth of the Canon EF series of auto-focus lenses. The Canon EOS Series auto-focus camera lens is fully electronically coupled with the body and uses a built-in power source to focus the lens, making it possible for the successful use of this technology. As the name implies, full-time manual means that all the time (AF or non-AF state) can be manual (focus), strictly speaking, full-time