I find the zoom lens pretty unusable. The JPEG quality is very poor and pixelated.  Is it just me?
Doesn't appear to functioning improperly. Quality is poor and the more you zoom, the worse it gets. I get that it is digital zoom, but I can't find any zoom level that is usable.

I find the zoom lens pretty unusable.
Your drone has two cameras, but neither has a zoom lens.
If you are referring to the tele camera, it has a small sensor which gives best results at ISO 100 and with good light.
Shooting in poor light and/or increasing ISO, increases noise and gives grainy results.
Quality is poor and the more you zoom, the worse it gets. I get that it is digital zoom, but I can't find any zoom level that is usable.
Using digital zoom would only make things worse.

Try shooting in good light at ISO 100 and the results should be better, but expecting teh digital zoom to give good results probably isn't realistic.

Labroides Posted at 10-25 05:31
I find the zoom lens pretty unusable.
Your drone has two cameras, but neither has a zoom lens.
If you are referring to the tele camera, it has a small sensor which gives best results at ISO 100 and with good light.

Yes, technically "tele". lol

I shot in full daylight at ISO 100.  At full wide it looks best (but still poor). But if I was going to shoot wide, I would use the wide lens. At any "zoom" level, it obviously looks worse. What is it's native focal length and how can I be sure I am shooting at that?

Shoot at 1x or 7x and nothing else. That's how you can ensure you're not using digital crop. You'll notice that there is a huge difference in quality going from 6.5x to 7x because it changes to the other camera. I wish DJI would give us the ability to shoot in raw on the 7x camera because I find this jpg useless in 80% of use cases.