Sigma 18-50mm f/2.8 DC Lens Review - page 4

I cannot say much about this lens compared to others at its wider settings.  Compared to my 12-24 Sigma this new lens is undoubtedly sharper and brighter.  Then again I already knew that my 12-24 wasn't good unless stopped down to f/11-22.  I think the real world tests will better tell the story of this lens as a general purpose kinda-wide-kinda-long lens.

One thing that bugged me about this copy of the lens is a easily seen blurry area on the right side of the frame, though only at 2.8-4.0 at the widest angles.  From the first shots I took I saw them in the crops.  Here are a few examples:
Full Photo (oh, that PF on the power lines)

Left Edge

Right Edge

What I seem to notice about these crops is that this copy of the lens is very soft at the right edge and a little soft at the far left edge.  As I stop down the lens the problem seems to fade until f/11 or f/16 when diffraction becomes a problem.  These shots are framed differently from the one above so this crop is of the bottom 20% of the frame, at 1/2 crop.  Yes, I know they're large but its the only way I could get the point across.

f/2.8

f/4.0

f/5.6

f/8.0

f/11

f/16

I also notice the vignetting in the f/2.8 and to a lesser degree the f/4.0 crops.  Yes, the lens does vignette wide open and then some.

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