Tamron Japan has just filed a new lens patent on Tamron 70-200mm f/4 VC full frame lens. This lens should be cheaper than Canon EF 70-200mm f/4L IS USM and Nikon AF-S NIKKOR 70-200mm f/4G ED VR.
Patent Publication No. 2016-126278
Published 2016.7.11
Filing date 2015.1.8
Example 1
Focal length 71.8092 109.9915 205.9615
F-number 4.0989 4.1033 4.1023
Half angle of 16.7567 10.8972 5.8621
Patent of Tamron
Positive and negative positive positive and negative 5-group zoom
Inner zoom
Inner focus
Vibration control
via: EG