X5 PDF

I don't know a lot about the setting up of PDF files and have always used whatever the default settings were for emailing invites to friends etc.

Since I have had X5 I notice when I publish to PDF and print, the graphic is slightly smaller and gives bigger margins than my original  [even slightly off set too so the graphic or text is not perfectly central]

I can't find a page set up for PDF is there one or is there a solution? Of course it may have been the same in previous versions of Corel but I just didn't notice.