HFT, meaning "High Fidelity Transfer", is a multi-layer anti-reflection coating system co-developed by Zeiss and Rollei. This occurred several decades ago at a time when Zeiss T* coating was new on the market and could only be applied at the Zeiss Oberkochen plant to rather small camera lens production batches. Rollei envisaged very large volume production in their then new Singapore plant and therefore encouraged this joint development.
Today the situation is this: HFT has become a well established trademark for Rollei's proprietary multi-layer anti-reflection coating. The optical performance of this Zeiss/Rollei co-development is so close to the performance of the original Zeiss T* that one can hardly detect any difference in all practical picture taking.
The Planar, Distagon, Sonnar lenses that Rollei produces under license from Carl Zeiss are all HFT coated by Rollei. All the lenses that Carl Zeiss produces for Rollei at the Zeiss Oberkochen plant are actually Zeiss T* coated. However, the designation on these lenses is "HFT" in the interest of remaining fully consistent throughout the Rollei product range.
Camera lens news, No. 13, Spring 2001. Publisher: Carl Zeiss Oberkochen, Camera lens division.