The Japanese Impress Digital Camera Watch published an interview to Tamron engineers who talks mainly about their new prime lenses:
http://dc.watch.impress.co.jp/docs/review/tamronsp/20150918_721493.htmlThe sample images can be enlarged to the original sizes by clicking them. The camera is not mentioned, but the image size suggests that it was either D800/8000E or D810. The texts are only in Japanese. Here are some interesting points:
1. They decided on the speed of f1.8, because an f1.4 lens with the vibration reduction would be too big, but they want the lens faster than f2.0.
2. They wanted the lenses to be able to get closer than the conventional lenses of this class.
3. The equivalent effect of vibration reduction is 3 stops on 35mm and 3.5 stops on 45mm respectively, which appears to be inferior to the 4-4.5 stops of Nikon VR lenses. They chose the better optical performance over the more effective vibration reduction.
4. In order to enable the lenses to get closer, they incorporated the floating element method. The challenge was that the major part of the optical system including the vibration reduction elements has to be traveled to focus, which makes the mechanism as complicated as those of zoom lenses.
5. They are planning to expand the f1.8 vibration reduction prime lineup.
Hope this would be of any help.
