Tamron has just announced the development of their first full frame mirrorless lens Tamron 28-75mm f/2.8 Di III RXD FE lens. According to TamronPhotoClub on Facebook, this 28-75mm f/2.8 Di III RXD Lens will be released in April to May, 2018. And it is to compete with Sony FE 24-70mm f/2.8 GM lens, while price is much cheaper than FE 24-70 GM lens.

From TamronPhotoClub: