My last contact with Sigma OS was with a brand new Sigma 120-400. It was disappointing and yielded a max of 1 stop efficiency. This is far form the results a Canon IS or Nikon VR can achieve.
The reduced magnification is an indicator of a change in lens-design. So, don't
assume that this new lens performs at least equal to the "old" APO design. If you want to have lens-based stabilization you have to change your lens-design and live with some restrictions that may make it harder to achieve a certain IQ-level
I'm not dissing this lens prematurely, all I'm saying is: You better wait for a reliable test before you get your hopes too high!
Thomas (beware: Nikon-fanboy and moderator!) My Lens Reviews
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