Firstly: Thank you, all, for chiming in with various answers to my question. Everyone seems to have taken a slightly different approach/perspective and all posts I consider valuable.
I'm a graduate of the Art Institute of Pittsburgh's commercial photography program (class of '73 IIRC). Probably most of you weren't even born yet.
I mention this simply as a way to indicate my experience with photography goes back to the antedeluvian period of film. I owned and sold more cameras than I care to admit; even owned a 4x5 Calumet which I carted around some state parks in NY; won't do
that again!
N Horuk suggests a bridge camera and I already own both an S9100 and S100fs Fuji (the latter of which is a lovely camera producing fairly nice results). But I'd like to get something sharper and the jump up from a 1/1.7" sensor to APS-C seems to be the way to do this. (I gave my *istDS to my daughter a few years ago and she's still loving it.)
dansamy suggests imaging-resource might have some DNGs and, sure enough, I did find the standard test shots (the one with the bottle of Muscat, cloth, crayons, thread, etc.). This was extremely helpful and did answer my question adequately. While I do see -some- improvement in detail with the K-3, the difference (to my eye and maybe no one else's) was only apparent at around 4:1 magnification in Lightroom. That was so magnified that the rectangle indicating the displayed area in the smaller thumbnail to the left was almost impossible to find on my 13" MacBook Air.
By the way, I found the S100fs test shot at I-R but it was a jpeg; still, it was (at the equivalent magnification) a lot better than I had expected and now gives me a better inkling of what I might expect from the Pentax (either K-3 or K-50).
So I'll look to the other benefits of the K-3 over the K-50.
The K-3 does have the earphone and mic ports but the money I'd save by going with the K-50 would more than pay for a decent HD camcorder that has both those ports; I can slip such a beastie into my coat pocket for the times I require one.
RonHendricks opines that the size of the K-3 DNGs might be a disadvantage and, as a long-time Mac user with 20TB of storage and backups already, I can "+1" Ron's warning. My S100fs DNGs are 13+MB. Double the storage requirement is depressing.
dms says "not a significant difference" between the K-3 & K-50 in terms of
real resolution and I think I will agree based upon the DNGs I'm seeing.
As the LiveView AF video (in the review here at PF) shows, IMHO, adequate speed—certainly better than I was expecting—I could still take some HD videos with the K-50 so I'd hold off on that HD camcorder until I have some experience with the K-50. As for still photos, I am a viewfinder kind of guy and, there, the K-50's AF seems to be fine.
So,
there it is; I guess I've made up my mind due in no small part to contributions from all of you who were interested in helping.
Thanks,
Barry