FileTable in 2016 and Transaction Log Backups larger than expected

I am testing using FileTable in SQL Server 2016 to store files of different sizes (could be pdf documents sized around 1mb to video files that are 200mb). When adding a file to the FileTable, I take a trans backup and it is always around 2x the size of the files added. Ex: 42mb file results in a 87mb tlog backup, 13mb file results in 27mb tlog backup. Has anyone used FileTable and noticed transaction log backups that were much larger than the files added. Files are only being added to the share. Nothing is being updated or edited between adding and taking a log backup.