Focus
Lenses on professional or old style cameras use helical grooves to alter the focus. The resistance, albeit smooth, you feel when you focus such a lens is the friction of the rotating barrels sliding through the lightly-greased grooves. That friction is bad with auto-focus systems, which all consumer cameras have, because powerful and battery-draining motors are needed to move the barrels. The quick response that is needed for fast auto-focusing is also difficult to achieve. Because of this, auto-focus lenses use lighter, more easily positioned, internal focusing elements with lighter, faster, power efficient focus servos.
The "focus ring" you turn is not actually connected to the focusing mechanism. It's a free-spinning ring with an optical or electromagnetic sensor attached. When you move the ring, a series of pulses is sent to the focus controller. The more pulses in a given time, the faster the controller changes focus. However, the system is not perfectly linear. If you turn the ring too slowly, nothing at all will happen because the controller ignores all pulses below a certain rate as noise. At the other extreme if you turn it 1/4 turn very quickly, you'll get more of a focus shift that if you turn it 1/4 turn at a more moderate rate. As a result of all of this, there's no way for the focus ring to have focus marks, nor is it possible to measure such marks yourself and be able to repeat them.
The same argument applies to the zoom controls on some lenses, such as the 16:1 and 3:1 zooms on the Canon XL-1 or the zoom rings on the Sony PD150.
These lenses need to be used with care, patience and understanding. You can't set marks, or focus by scale. Slow, fine adjustments may do nothing. But with practice and perhaps some adjustment of operating style, most people can learn to use if not necessarily love these lenses.
With the zoom on the XL-1 you'll get better control and smoother operations if you stick to the zoom rocker on the handgrip than if you use the zoom ring on the lens. Some folks are taping over the zoom ring entirely and only using the rocker. The zoom rings on the PD150, is almost as good as a "real" zoom control. You still can't set marks with them, but they're good enough for slow ramps and smooth accelerations. Again the rocker may be preferable.
If you don't like it you can always buy a real camera with a real lens (pictured above), like the Sony DSR-300, the Panasonic AG-DVC200 or the JVC GY-DV5000. Speak kindly to your bank manager thought.