Shallow DOF

These lenses would have been hand made.. The elements would have been hand ground and polished from a flawless solid block of optical glass, more than likely bought off Zeiss..The lens barrel hand turned on lathes from solid alloy.. Then assembled by craftsmen not production workers..

These lenses would be in the Rolls Royce (or Mercedes being German) class as opposed to Canon L lenses being Toyotas..

So how do you shoot a lens that requires a micrometer to find the plane of focus?

Very carefully. But, with LiveView and 10x, no problem, unless the subject moves.