Many have asked about an SDK method to convert PDF to TIFF during file import. While the LF SDK does not have a built in method to convert PDF, it can be easily done with Ghostscript before import. Below is a link to a project created in VB 2010 Express using 32 bit version of Ghostscript.
Download 32 bit version of Ghostscript 9.0 or higher. Install it and then copy the gsdll32.dll into the project folder. Then add the dll to the project resources as shown below.
Once added, open the DLLs properties and change it to always copy.
Remember to include the DLL with the EXE file if you install/move the program.