Not to put words in Cary's mouth but I think he is trying to tell you that there is likely nothing wrong with the lens or the camera. However they both need a lot more care in setting exposure and associated parameters to get the most out of them. The GH5 is a very complicated camera and it is very easy to get images much worse than a simpler camera. I have just got a GH5 a couple of weeks ago and am still learning what to do with it. By the way I am 75 years old and into photography since I was 15, film cameras since I was 23 and video for the last 37 years. Not a pro but certainly not without some experience and ready to learn as new things come out that need different approaches to get the most out of them.