[davidmanze]

FWIW ... after having used the lens out there over the weekend - the experience tells me - once again - that DSLRs and EOS cameras in particular just can't focus accurately with ultra-wides. The margin of error is HUGE and, of course, it was especially bad with this large aperture Sigma lens.

Things are fine with close-up but for middle-ground scenes (2-3m) things are going down the hill rapidly. The camera is just focusing too far to the rear.

 

 Wide angle lenses seem to cause the most focus problems and Sigma have forged themselves a reputation for AF inconsistencies with repeatability issues with some of their recent lenses, large apertures should have helped to some extent. When calibrating AF on a zoom I start at the wide end where the adjustment make the greatest difference. 

  But even my Sigma 150mm tele-macro suffers, it does very well until you get to less than 3 mts......then it front focuses agogo, at 2.5 mts you need like -17 then it quickly goes to the max setting with still not enough compensation.........it's just enough to spoil it as a portrait lens (at least one you can rely on)

  At macro distances it's fine again!

  

 

 

   But I don't want to unearth a can of worms here......please? :mellow: .....let's use another thread for that!