Migrating from TFS to Git
There is a direct way its called git-tfs and it's up on github.
You just do a
git tfs clone <tfs server> <tfs project>
I recommend getting the source and adding it to your path separately so that you can debug it for any strangeness, but the code is pretty easy to step through.
I had a file that was an msi that was 500 MB that the client stored in tfs, that wouldn't convert, took a few hours to narrow it down.
I wrote blog on migration of source code from TFS to Git, by maintaining your check-in history. Hope it will help:
Blog: TFS to GIT Migration