see also:

• Sony FE E-mount full frame lenses
• bokeh

• special portrait lens with unique circular peripheral ND filter built in which acts as an apodization element which smooths out blur of out of focus highlights to improve bokeh, but which also reduced light transmission by 2 stops so at f/2.8 it is really f/5.6 while depth of field (DOF) wide open is really akin to f/4

• special purpose 100mm f/2.8 AF lens
• optical image stabiliser
• unique circular peripheral ND filter built in which acts as an apodization element
• 11 rounded blades
• extremely flare resistant

• https://www.dpreview.com/news/2820818690/sony-fe-100mm-f2-8-stf-bokeh-demystified
• http://www.diyphotography.net/makes-sony-100mm-2-8-stf-lens-special/
• https://www.dpreview.com/samples/4612606132/sony-fe-100mm-f2-8-stf-gm-oss
  • some severe AF accuracy issues on Sony a7R II full frame mirrorless camera
  • “AF performance plummets indoors - understandable given that phase detection depends on peripheral light rays, which are the exact light rays this lens' apodization filter filters out”
  • sharp wide open IF focus is achieved accurately
  • mild lat CA
  • minimal axial CA
  • bokeh wide open is almost too buttery-smooth Gaussian bokeh, bokeh has more character stopped down even by 1/3rd EV at T6.3
  • best in good light and the wider DOF wide open makes it better for couples
  • not great for dim lighting as not only wide open is T5.6, the AF will struggle