Originally posted by boriscleto Maybe the red ring is for the HD DA Limiteds only.
No, the new HD DA 16-85 WR and the DA HD 55-300 WR have the red ring too. I think it's just a matter of inconsistency. At some point in time Hoya/Ricoh/Pentax decided to distinguish lenses bearing the new HD coating with a red ring, this decision has recently been reversed and a green ring has been reintroduced on some lenses (the new FF zooms and the HD DA 18-50 WR DC RE). A similar inconsistency exists with the DA/DA L distinction. DA L is usually understood as a cheaper kit lens lacking quick shift, a metal mount, a dedicated AF motor (DC or SDM) and the HD coating. However the DA 35 f/2.4 and DA 50 f/1.8 fully fit this description and are still labelled 'DA', conversely the new DA L 18-50 kit lens features a DC motor and is still labelled 'DA L'.
It's getting a bit confusing