Most:
-the price
-flexibility the zoom ring / focus
-rapidité of focus
Cons:
-a little chromatic aberration on the sides
-Slight image distortion (easily corrected by applying a treatment adapted to the objo)
Appraisal:
Some blame this goal to be a little below its slightly more expensive brethren, that the motorized focus is noisy, and that there are aberrations / distortions.
Without being totally false these statements are the responsibility of professional use. For my photo enthusiast is more than enough and I think the record will be at the appointment.
The real problem is still behind the lens and not the goal itself.
To Conclude:
If you buy it, make tests before using it for good. Play with the depth of field, test prospects. With this level opening the record will be really different if you angle the picture horizontally or vertically.
For the price this is a good target for amateur. Even at 3.5 blurring device remains correct and well own center. The larger diameter (O77 mm think about it if you buy a UV filter) lets enough light to compensate.
I like!