Originally posted by Tony Belding s. Q lenses don't have anything like that [focus scale], so it would be guesswork.
Actually, it's very easy to add a useful pseudo-focus-scale and use it to predict DOF and/or hyperfocal points for selected distances you expect to use. Sort of like 'Scene Modes' except for focusing convenience.
Simply focus accurately on a few points at the distances you commonly use and mark them with a fine point marker on the focus ring and add a a fixed index mark. My 03 has such reference range marks added which greatly speeds manual focusing for frequently encountered situations.
Record the markings for future reference. Add notes for DOF at selected apertures if desired.
(And before someone starts in again about how sloppy and inaccurate that might be, remember, there's absolutely nothing preventing you from further refining focus by any and all means available.)
On the occasions when I've used prepared 'range marks' in the field I've used an erasable label on the bottom of the camera body for quick reference notes.