2012.02.06 22:36 "Re: [Tiff] libtiff tiff2pdf vs CTAN tif2eps + ps2pdf", by Bob Friesenhahn
When converting from TIFF->PDF, the entire TIFF infrastructure/file format is removed and only the bits/pixels are left. Whether those pixels are touched is up to the conversion tool and whatever transformations (color, compression, etc.) it wishes to perform - but in general, it's not necessary.
What about the case where the TIFF image is comprised of multiple strips? In this case, it seems that some translation is necessary.
GraphicsMagick Maintainer, http://www.GraphicsMagick.org/