Disappointing! 73

I can not discern any improvement to the old version in the type II of this lens.
On the contrary: The corners are not sharp at all focal lengths at maximum aperture of the Canon EOS 5D Mk.II and that does not change even when dimming. Compared with an open aperture and stopped down to f 8, the old version is better and at 24 mm each approximately equivalent in 12mm. Distortion at 12mm is much more visible in the new version. In addition, my Sigma 12-24mm II shows an uneven centering. Links the image is visible sharper than right. Given the price of the equivalent value is no longer appropriate, even though the extreme focal length is sexy and also unrivaled. And that with a freshly revised lens!

This is just the big problem at Sigma and these extreme viewing angles: In the tests of scientific journals handpicked specimens are tested by the manufacturer, which are highly praised and rightly so. Understandable, since they are available from the Company and provided by them. The reality is unfortunately different. This lens has probably like the old version also much too high reproducibility, ie the customer gets a lot of money for substandard quality. This Sigma is not alone, even several Canon L lenses have this problem, as I have myself tested, such as the EF 4,0 / 17-40 L and EF 4,0 / 24-105 mm L. From "old" Sigma 4.5-5.6 / 12-24 mm, I had a total of 3 copies. All had a clearly visible difference in image quality.

My tip: Go to your local dealer, test different specimens and take the best with. Everything else is risk and can be a letdown.

Another note on the Amazon description "with 82 mm filter thread". The lens cap is in two parts. If you take the cover off, you can instead use a filter screw. However, it has no vignetting at full frame only at 24mm. In addition, compared to the old version of the backing sheet filter holder has been saved.