Originally posted by normhead I guess if you shoot a lot of brick walls, or rectangular shapes, barrel distortion would be an issue. I'm doubting a landscape photographer is going to care much... in the image above, I look at it and say "barrel distortion? What barrel distortion?" No doubt you can prove it's there, what you can't prove to me is that it matters to anyone. Now I don't doubt someone has made a distortionless 12 mm lens.. just because I haven't seen it doesn't mean it's not true.. but part of the beauty of this lens is it's contrast, colour cast and a few other intangibles. I'd be a lot more impressed by the statement about the lack of barrel distortion if you said the example lens had all the intangible qualities of the 21 Ltd. and less barrel distortion. I'm really not interested in having less barrel distortion which I really don't care about, to get a lens that takes dry , flat pictures, with no barrel distortion. If there is a trade off, and I give up things I like for things that don't matter, I'm not buying it.
As I said, I'm sure there are lenses with less barrel distortion, but will I like the images as much? And since you seem to be their champion, I'd ask, do you like the images as much? Any examples that illustrate your point?
This stuff comparing a lens with a bit of barrel distortion to a car with no seat belts is just silly. Just post the photos, no dumb analogies needed.
Easy, tiger. As I said, I agree the DA 21 is a great lens.
I use the Sigma 12-24 (full-frame) on my D700, and while not completely free of distortions, it's pretty
stunningly straight at 12mm and pretty much perfectly corrected at 21mm.
I agree that for landscape photography barrel distortions aren't a huge deal unless you're placing trees at the very edges of the frame, but I also do a lot of architectural shooting and it's very noticeable in those cases. The reason I'm using my Sigma on the D700, instead of the Nikon 16-35/4 VR that I owned previously, is that the distortions of the Nikon lens made it entirely unsuitable for architectural photography.
Some from the Sigma (most at 12mm, which is WIIIIIIIIDE on FX):
Obviously, it's no fair comparing the FOV of the Sigma at 12mm on FX to that of the DA 21 on APS-C, but I think the Sigma renders beautifully, and as you can see it's very well corrected.
On the other hand, it's also huge and heavy compared to the DA 21, and that small size and low weight is something you won't find with many other lenses in the 21mm area (check out the Sigma 20/1.8 for instance... it's a beast).
Every lens has pros and cons. For me, distortion is enough of a con to outweigh some very significant pros.