The 8mm and VHS recording formats are completely different. The information on an 8mm tape is actually placed on the tape in a different way than VHS. For this reason, there is no cassette adapter available that will allow an 8mm cassette to play in a standard VHS video cassette recorder (VCR).
NOTE: The only VHS adapters on the market are for use with VHS-C tapes. VHS-C tapes are used with VHS-C camcorders, which are not manufactured by Sony.