Thanks for your reply. Could you advise me some article about artefacts issues, so i can read and understand the problem? Because you said that you see artefacts and i'm looking on that photo and don't understand what are you talking about and how to see that artefact.
Artifacts in your case are compression JPEG artifacts, which are small blocks of pixels of similar colour grouped together in order to save space. Smartphone cameras use JPEG compression to save space. The result is that when you enlarge you can see this effect. This looks like from a smartphone camera.
The sky shows small blocks of colour which are a type of artifact.
Read this. It's a quick explanation of artifacts.
A google search will give you a lot of examples.
I don't see any focus problems.
i understood and found it, thanks