Thanks for bringing this to our attention! Thomas Lofstrom has recently uploaded some amazing video footage. Did you see this one of his, from TBF? The cameramen are shooting on stage with handhelds from several locations. There are some very good close-ups and tight shots. The audio is from SBD.
This incredible video montage of TBF performers is 1:01:48. John Hartford footage starts at 0:35:30.
The Festival Tapes 7.0: Bluegrass SamplerKate Wolf, Jamie Brockett, Crossroads, Sons of Thunder w/Jimmy Ibbotson, New Moon w/Tim Goodman, John McEuen, Dan Crary, Doc Watson, Reasonable Band, Free Mexican Airforce w/Peter Rowan, Steve Goodman, Doug Dillard, Eclectricity, Hot Rize, Rising Faun String Ensemble w/Norman Blake, New Grass Revival, Ricky Skaggs band, John Hartford.
Mr. Lofstrom forgot to mention Doc Watson, and Ricky Skaggs band, so I added there names to the above list. This amazing video tape footage appears to be from the 7th Annual Telluride Bluegrass Festival in 1980.