S J Gwilliam wrote:
>
> The story goes.....
>
> I bought a Sigma 12-24mm lens and was very impressed by the build
> but equally unimpressed by the fact that the image was really soft
> . Actually, it was really sharp in the bottom right corner but
> progressively got softer in the other corners. Top left was just a
> blur.
>
> The retailer replaced that lens for another 12-24 which is much
> improved. However it is still pretty soft in the corners at 12mm
> even at F8-F11 and does not have good contrast.
>

Try the Nikkor 12-24 - it's way sharper and more conrasty - as the MTF charts indicate (10 lpmm indicates contrast, 30 lpmm indicates sharpness):


http://w6dkn.net/777/12_24_MTF.jpg


http://w6dkn.net/777/Sigma12-24_4.5-5.6EXDG_MTF.jpg


= Dan =