Thanks for your quick responses.   Yes, the regular log backups truncate the log, but don't shrink its size on disk.  Our database has a data file of about 11 gigabytes with the log at 8 gigabytes in spite of the regular log backups. 

When I took the steps mentioned, the log file went from 8GB to under 1MB  -- the question is whether it will fairly rapidly wind up at 8GB again or just grow slowly until I do this process again.

 As far as point in time recovery, at the point in time of the full backup, prior logs wouldn't be needed, and our database maintenance plan will start right back in doing 6 log backups per hour going forward.