Manga on prs-500

[anix]

Hi,
I have been putting my manga on my prs-500 and up until now it has been great. In the series I just uploaded, however, the font is must smaller and I sometimes need to zoom to read the smaller parts. When I zoom, it does not seem that the full resolution of the files is being shown - it is highly pixellated on the reader but not on the lrf files on my computer. Is this normal or do I have some obscure settings that is causing this?
I used comiclrf to convert from cbz files, with the default settings.