All kinds of images can be printed as PDF files and that also includes pictures or digital photographs. Even digital raws, such as .cap files recorded by Phase One cameras can probably be exported as PDF document. However, the resulting file will be pretty large and you would be better off with first exporting it as JPEG image before creating PDF file.
Convert Phase One RAW image file to Adobe Portable document format.
We have found 2 software records in our database eligible for .cap to .pdf file format conversion.
Microsoft Windows software - convert cap to pdf on Windows
Adobe's professional tools for RAW image management and post-production
Convert from cap file format
The tables with software actions are a good pointer for what a certain program does with various file types and often may give users a good hint how to perform certain file conversion, for example the above-mentioned cap to pdf. However, it is not perfect and sometimes can show results which are not really usable because of how certain programs work with files and the possible conversion is thus actually not possible at all.
Apple macOS / Mac OS X software - convert cap to pdf on OS X
Mac version of Adobe' professional digital photo editing tools