I use LyX 2.0 and export with pdflatex.
When writing standard text and exporting to pdf, the font gets rigid. Text written in math mode, though, is exported crystal clear. I've tested that on several computers – but they all show the same problem.
I can't get it, since it's the same font in both cases. Even when choosing italics for standard text, which is how math mode text is showed, I get the same result.
I attached the screenshot below , if for some reason the difference will not show on the pdf itself. (obviously that compromises the quality, but the difference can still be seen clearly).
Best Answer
It appears that the problem is that your LyX and LaTeX installation is using bitmap fonts instead of vector fonts for text. Try setting the default roman font for the document to Latin Modern Roman in the document settings.
Document > Settings > Fonts > Roman > Latin Modern Roman