I haven't had much time to play with the 300 yet, but I took it out yesterday for my daughter's tennis lesson. 3PM sun was pretty harsh, reminding me as I struggled to see anything that only the best EVFs give me any chance to compose reasonably well as a glasses wearer with terrible eyesight. So I ran through some throw-away type shots, just to see what this little guy can do.
600/2.8
226/2.8
600/2.8
308/2.8
.
226/2.8
Certainly no revelations in terms of image quality, but I think Panasonic is getting a lot out of this sensor, just like on the FZ200.
Other quick comments about the camera: Ergonomics are great for me. Small, but chunky enough to hold on to. Right amount of direct controls for a super zoom (4 Fn buttons help). Screen is very good. No major negatives other than EVF, which is more the nature of the beast than a flaw with a particular camera. I dabbled a bit with 4K photo mode. Seemed to work well. I will try to post up an example or two later.
My limited test run doesn't make this camera choice a slam dunk for me, but I didn't think it would. No real surprises. It is not so useful in dim indoor lighting, but I didn't buy it for that. I suppose I don't see much reason to choose the FZ1000 instead. What does creep back in to my mind is buying an old Canon 40D and 55-250 zoom for maybe $300. No fancy bells and whistles (touch screen, flip screen, any kind of video, much less 4K photo, etc), but it would be my preference for shooting in the bright sun, which is where the FZ300 will be used a majority of the time.
Of course the versatility of the FZ300 crushes the 40D, with ability to shoot at 25mm, instead of 88 min, and things like video, wifi, etc.
Oddly enough, this little session sort of validates (to me) Sue's choice of the P610 (even though she doesn't like it). It's easy to get to the point where you say "Well, if I am going to accept a camera that is this limited by the sensor I might as well get one that really offers up something to compensate for that." 1440mm equiv zoom makes things interesting, I suppose.