Also pre 1990 Tokina was an unknown. The company is actually owned by Hoya but they try to hide the connections even today, but a recent Press releases stated that Hoya wouldn't merge Pentax with Tokina, which says rather a lot

Pre 1990 Hoya had introduced a range of lenses under their own name, which quite annoyed every other Japanese optical company as Hoya's Glass Division makes and sell optical glass to them all.

However Hoya made some serious design and production errors and skimped on the Multi-coating, not coating all the internal glass/air surfaces, many suffered from bad flare, some lenses were worse than others and after a short time Hoy ditched the whole range. They went back to the drawing board licking their wounds and quietly solved all the issues before re-launching a lens range, this time with the Tokina name which they already owned.

Ian