Guess what? I
think my K-01 50-200 lens is 'parfocal'.
If this is true, it is REALLY NEAT. Because it means that I can zoom it all the way out... to 200mm... focus carefully... and then it will stay in focus after that at any zoom setting, all the way down to 50mm...
without having to touch the focus ring ever again.
Just tested it in dim interior light, with the lens wide-open at f/4, handheld at 1/20, ISO 800. The top pic below shows the image -- after focusing at 200, then zoomed it back down to 50mm ... and the bottom pic shows a 100% crop of the Starbucks cup I focused on... still sharp! So move over, Steven Spielberg. Hollywood, here we come!