1999.06.01 16:05 "[Fwd: Tiff to PDF conversion]", by Tim McNerney
You don't mention any details about the type of TIFF images you have. PDF handles G4 images directly, if you are dealing with binary TIFFs. Even better, you can pull the data directly and just put on a PDF wrapper -- no need to bother with compression/decompression.
I believe PDF also handles lzw compressed images, but that gets into other problems with copyright issues and all.
One of a solution is to use 'tiff2ps' program provided with the tiff library and then to use the Adobe distiller to create the PDF file.
This shouldn't be necessary and won't be terribly efficient. You have a lot more steps in the chain to get to the final image. I know if I were doing 150,000 images, I'd put a bit more time in up front to get things working. But it should work as a solution and require minimal work to set up.