[matthew]

I was browsing dpreview's lens test of the 14-42 "kit" standard zoom and was surprised to see a 'pro' comment of "Proper manual focus ring and non-rotating front element". I checked the main body of the review; they knew it was electronic but liked the way it was damped. From the review:

The most unusual feature of this lens's operation is the focus-by-wire manual focus system, which drives the focusing group indirectly via the lens's autofocus motor (as opposed to the direct mechanical connection found in most lenses). As a consequence, the feel of the manual focus ring never changes, regardless of whether the camera is set to auto or manual focus, or the focus has reached the limits of its travel (either close or infinity), and this lack of tactile feedback can be a little disconcerting in some situations.

(It's funny that out of context that reads as a negative, while the overall review makes it sound like a positive thing...)

Possibly the most sophisticated use of the focus-by-wire design comes when shooting with a combination of one of the highest-grade Olympus telephotos, continuous auto-focus, and manual focus with the latest generation of E-system bodies. The MF+CAF combination lets the photographer manually pre-focus the lens and hold that position before engaging the autofocus. (Older bodies needed to have the CAF active and 'tracking' a pre-selected point until the action started.) Any non-SWD lens can do that seamlessly, but the top lenses also have electronic focus-hold buttons around the barrel that temporarily halts the CAF. It's a system that lets the photographer take more control over the tracking of moving subjects. Hopefully Olympus will eventually come out with a bullet-proof predictive focusing system, but until then it's a useful ability.