File Number Limits on NT 4.0??

Is there a way to calculate the maximum numbers of files per directory when using long filenames and an NTFS NT 4.0 volume? I am running into what APPEARS to be a limit when collecting large numbers of imaging files to a directory for distilling down to 650MB groups for making CD’s. I don’t think I have ever seen an actual formula (or even a reliable rule of thumb). Any ideas?