6 out of 10 points and not recommendedgood price, good quality picturesslow to autofocus, rattly contruction, use with third-party cameras, Sigma warranty
I purchased this lens to use with the Sony NEX5-N about 7 months ago. The lens has been working nicely and to our satisfaction for a lens of this price range. But a few weeks ago the camera started to not recognize the lens (except intermittently), even after cleaning the contacts on camera and lens with alcohol. (We have had no accidents, drops, bangs, extreme climate conditions...) We tested the camera with Sony lenses (without problems) and then took the Sigma lens to the authorized Sigma dealer/repair center in Chile who determined that the lens has a firmware problem and needs a firmware update.reviewed January 31st, 2013 (purchased for $199)
This is where we discovered that our 1-year worldwide warranty for the lens is useless. We have two options:
(1) Have the lens firmware update made under warranty - which requires that the lens be sent out of the country - at our expense -- for the equivalent of over $300 -- more than the price of a new lens!
(2) Have the firmware update made in Chile, but at our expense.
There may be compatibility issues with third party cameras, such as the Sony NEX-5N. Or simply, unreliable construction / firmware. We have not used the camera/lens under any kind of condition where you might expect to cause problems.
The Sigma worldwide warranty is completely inadequate in parts of the world.
I do not recommend purchase of this lens until the above issues are resolved.