InDesign (and in5) treats PDF and AI formats as raster images when exporting, so upping the Image Quality setting is an appropriate fix if your vector images do not look crisp in the output.
Alternatively, you can 1) open the PDF or AI file Adobe Illustrator, 2) copy the content, and 3) paste it into InDesign to keep the text live and editable in InDesign.
To convert entire PDFs to InDesign, use a tool like PDF2ID.