I managed to resolve this issue. There was probably no problem with Evernote app, but I'll describe what was the problem. I had custom Android ROM (OmniROM) and there is build in camera app. It work quite well. I had only problem while using it with Evernote, but I found that many people have the problem with camera focus itself. I installed this updated camera app and whiped all cache (as is said in instalation notes of this app). Now everything works great in Evernote too.
Hello, I use document scanner i Evernote Android App on my Samsung Galaxy S3 to scan receipts almost every day. About month ago or so - scanner started behave differently. Now it loses focus in camera almost every time and scans are very blurry. I tested document, postit and business card scanning - all they get blurry images. Only normal camera mode (also in Evernote) works fine.