Here's some links to a number of tools that you might use to make PDFs easier to read on your Sony:
PDFLRF
Rasterfarian
PDFread
SoPDF
PaperCrop
I use PDFLRF for scanned PDFs, and SoPDF for PDFs that are already text-based, personally. And I pretty much always get usable results, even with academic PDFs with mathematical formulae, etc.