Originally posted by kenafein I owned the DA21, and I sold it after purchasing the Sigma 19. I liked the rendering of the DA21 slightly more. I think the bokeh was also smoother, wide open. I think the Sigma is sharper and very close to the quality of the DA21, at a much lower price. It was good enough for me to sell the DA21. Since you still have K-mount cameras, you might want to get the DA21. It can still be used on both cameras, but the Sigma will only be useful on the NEX. I wouldn't pay more than $400 for a DA21, however, I don't think it;s worth anymore than that.
Thank Brent, I think will keep Sigma at $99 instead of spending $400 on DA. I will be anyway using Sigma for landscape so bokeh is not important.