12-35 at f2.8 is this the quality others are getting?

RamblinR wrote:

Images shot at the same distance on a tripod at 14mm with focus point in the centre of the image. The 12-50 is at f3.8 which is wide open for this lens but if I have to stop the 12-35 down to f4 for a good image what would be the point of owning it.

How have you found this lens at f2.8? Should I return this copy (never had to do this before with any lens I have purchased).

One image shows the full scene (and as you can see the crops are quite deep into the image). Others are screen shots of the 100% comparison from LR4.

12-35 vs 12-50

14mm vs 12-35

Full Scene