Hi Gerard.
The video output isn't as good as it could be, but there are a few things you can do to make it pretty reasonable - although it involves some post-production work. This is what I do:
- Don't use the in-camera software shake reduction, to remove the jelly effect. De-shake in post - there are a number of free solutions out there.
- Use a basic shooting mode such as the 'muted' mode to minimise non-recoverable bright whites and dark blacks, then adjust alpha, saturation and contrast in post.
- Use the progressive capture frame rates up to 30fps. The K-3 has a 60fps but it's interlaced which can cause issues.
- Shoot in manual so that it maintains the exposure you set - much better than the camera auto-adjusting the exposure, which doesn't look good.
- Use a shutter speed that is (1/frame rate)*2, so for 30fps you'd set 1/60 second, which gives a good cinematic look.
- Pre-focus using focus peaking, don't try to use AF in video mode. If you need special focus effects from say distance to close-up, take the time to learn manual focus pulling with your particular lens.
- Take your time!
Hope this helps.