Originally posted by dubyam I can't speak to the K1's inherent video capabilities or quality, but I can offer the following thoughts in general.
The very best still camera video capabilities are still only fair compared to even a good (not great) video camera in terms of sound, stabilization, and overall quality. The same can be said for video cameras which snap still photos, as well. I've long been a firm believer in having and using the right tool for the job. In our current digital age, it's pretty easy to both afford and carry along a small digital video camera capable of taking good quality HD or even 4k video. I have an HD JVC I routinely carry along in my Pentax kit. It has good optical zoom, records to an SD card, and is about half the size of my 18-55WR kit lens, and about a quarter the weight. It makes no sense to me to sacrifice the quality of video by taking it with my DSLR, just as I don't use my video camera to snap still pics, even though it has the capability.
Just my two cents. If you really want a DSLR for video, I've read that Canon is the best at this combination. But its still not as good as a good video camera.
I would, respectfully, take issue with some of your statements. Either the Panasonic GH5 or the SONY a7III will deliver video, both 1080 and 4K that rivals professional standards. Short of professional ENG and run and gun type cameras that cost several thousand dollars or more, I know of no small affordable cameras that equal the Panasonic or SONY in delivered video quality. Both of those cameras offer multiple video recording options, have mic inputs, HDMI outputs for external recording if desired. The SONY in particular, at 24 megs full frame, delivers superb images with lower noise than a K1, or just about any other DSLR or mirrorless, for that matter, including your JVC, which likely has a much smaller sensor with inferior dynamic range and S/N performance. And Canon isn't even in the running at this point unless you get into a 5DmkIV, and it's still outperformed by any of the SONY mirrorless bodies in dynamic range and S/N. Additionally, when shooting in FF mode rather than the Super 35mm mode, the video is shot internally at 6K and down sampled to 4K. The output is superb.
It's also worth noting apps are available that allow a smart phone to provide wireless monitoring and control of both the SONY and Panasonic GH5. As for the K1, as formidable as it is as a still camera, its video capabilities are extremely limited and the actual resolution of its 1080 output is not even up to studio 720P quality, falling somewhere between that and standard def 480P.