Samsung D-XENON 12-24mm f/4.0 ED AL Lens

The Samsung D-Xenon lenses are mere rebadging of equivalent Pentax lenses and therefore absolutely identical products. The price range is similar as well. The 12-24mm shares the same formula as the Tokina 12-24mm, which is rated as one of the best wide angle zooms today. The website DPReview rates the Tokina as optically superior to the Sigma 10-20mm and the Tamron 10-24mm.
It shows very limited distortion and very good details. The Pentax/Samsung should be at least as good, with at least as good coatings as the Tokina and better construction, which explains the difference in price.