Jim proves that perpetually changing camera gear is futile & counterproductive.
Since my Rikenon 35-135 push-pull zoom cannot shoot video unless wide open (a bit limiting, I'd say!) WRONG again - works fine but not in P mode!, I went browsing for another similar option. I found a one-day-only discount on a Vivitar 28-105, also f/3.5-4.5 with a 'true' Pentax A setting, for a similar price to what I paid for the Ricoh. Its serial number begins with 77, a sign that this was manufactured by Kobori. I had known of Vivitar from my past SLR film days, and knew that Series-1 was highly regarded for a time - but Kobori was not a familiar name. The web has a few notes about them but not many. What I read was quite encouraging for other Vivitar 77xxxx lenses, whether Series-1 or not - so the 28-105 is on its way to me. Hopefully soon I'll get to a point where some lenses are leaving the building, but for now it's net-import time.
In other news, it's getting autumnal again in the northern hemi; here's a fine golden backlit shot.