http://www.eoshd.com/content/9653/nikon-d5200-review
^ Look at the pros & cons in Andrew's review for D5200.
- Basically, you don't want to shoot with flat profiles with D5200, but rather use standard profile or a profile close to standard and get it as close to what you want already in camera with D5200.
http://www.eoshd.com/content/10824/panasonic-g6-review-the-gh2-redux
- what my own eyes tell me in the test footage is that G6 will have a little less chance of moire occuring than on a D5200 (or a GH3 for that matter, like Andrew's tests show).
Short summary:
G6:
- if you want more possibilities for videos in post - get G6.
- sensor very good for stills
- 1080p at 50/60 fps can be used for full hd slow motion. Only G6 and NEX cameras have that feature around the same price level.
D5200:
- if you don't want to push shadows and do as much in post, D5200 will be great
- one of the absolutely best sensors for stills found in entry-level cameras.
- in stills mode, you'll need to shoot around ISO100 to ISO400 to get an advantage with dynamic range. The higher up the iso goes, the more similar the dynamic range will be to that of other cameras. This is true for stills at least, and I'd assume it goes for video mode as well, since it's how the sensor behaves.
- as long as you keep to standard profile, it won't have as much noise and will be quite comparable to a GH3 according to Andrew's comparison.
For stills: I've shot with DSLRs for a while, and you can get good results with less Dynamic Range and less good color reproduction. Higher DR and better color reproduction just makes it easier to get a great shot or rescue one where you missed a bit with the exposure. In other words - you'll get great results from stills with either camera if you learn how to handle them.
My recommendation is to get a feel of the cameras in a shop, usually helps a lot to try to get a bit comfortable with a camera before buying. Also ponder about their weaknesses and strengths and figure out what's most useful for your way of using it. If you want to grade and tweak your video footage more in post, G6 will be the better alternative.