Question: is tamron 18-400 full frame?
Answer: The unprecedented 400mm telephoto reach is equivalent to a stonking 600mm in full-frame terms, when the lens is on a 1.5x crop-sensor Nikon like the D3400 or D7500, or a 640mm when on a 1.6x crop-sensor Canon like the EOS 1200D or Rebel T6i.