Originally posted by Ash the 70-200/4 is being worked on for the Pentax FF. If that's the case, perhaps later this year or early next year there will be a good lightweight counterpart to the 28-105.
The Nikon 70-200 f4 weighs 30 ounces; the Sony 70-200 f4 weighs 29.6 ounces; the Tokina 70-200 f4 weighs 31.7 ounces. In other words, the typical 70-200 f4 zoom lens comes in at nearly twice the weight of the DFA 28-105 (15.5 ounces). Hardly a lightweight counterpart! It will only be lightweight in comparison with the DFA* 70-200 f2.8.
The roadmap says it will be available in the spring. Despite all the hand-wringing about lens delays with Ricoh-Pentax, I'd say there's a pretty good chance we'll see it in the spring. It's the star lenses that get delayed. This is not a star lens, so better chance of not getting delayed.