Not only is it good, I believe Sigma is now on track to become the premier maker of high resolution premium quality dslr lenses.
It started (for me) with the astonishing Sigma DP2M, with edge to edge sharpness I had not experienced before with any other camera. This camera literally changed my expectations and even now it is so far ahead of any comparable camera (and other cameras one would not have though of as being in competition), I almost gave up shooting digital medium format. If you don't own one, my suggestion is to get one.
The DP1M and more recently the DP3M followed, each with outstanding lenses. Recently following the acquisition of my D800E I have enjoyed excellent results with the Sigma 85mm F1.4 and now the 35mm F1.4.
Sigma clearly know what they are doing.
Quentin
Agreed that Sigma is onto something, and IMHO it isn't just "sharpness" and "resolution" but also character -- they do seem to have something Nikon does not always get:
>My Nikkor 35/1.4 G was sharp but had no juice;
>My Nikkor 50/1.4G is relatively sharp and has some juice;
>My Nikkor 85/1.4G is a freaking laser and has major mojo;
>This new 35 Sigma appears to be sharp and have juice;
>From experience on C, my 50/1.4 Sigma while not as sharp as my current Nikkor 50/1.4G, definitely had better juice.
Ergo, I am considering replacing my 50/1.4G with the Sigma 50 -- I use the 50 a lot. But then when I've had a good 35, I tend to use it instead of the 50 -- I rarely carry both -- so maybe I should just add the 35 Sigma? Decisions...
I just finished reading the (so far) 3 pages of the thread, and I am glad that the "juice" bit got added to the "technical" bit that occupied the first part of the thread
I agree with Quentin that Sigma is onto something with the DP1, 2, 3 Merrills which I have and enjoy very much (the 3 is on its way). To me, 28-35 are very useful focals and ones I use a lot, but also (especially so with the 35) focals where it is difficult to find juice and character in a lens; the DP1 Merrill has a very good lens, and the Foveon results are incredible as far as micro-contrast and sharpness go, I'd like to see that coming out of my D800E as well in this range!
I am working on my recent Death Valley images, and I found myself using a lot my 35 Nikkor, which is very good & sharp over the frame but so-so when it comes to character. I have been looking with interest at the Sigma 35, but I agree with Tim, controlled reviews are very limited in real-world representation of what a lens can or cannot do; plus, the QC issue scares me a bit. Not living in the US or UK, it is very difficult for me to try-repare-replace lenses, because techs here (Istanbul) have very little idea when it comes to high-end (and high-expectation) equipment, unfortunately. They'd just say "well, it focus, so it works" and that'd be enough for them... :wtf: (I still remember the war I had to put on to have my original D2x replaced when they couldn't get it to focus due to Nikon making a mess of the AF module...!). So, I normally get my equipment from Milan, Italy which is way better, but again I am not going there every other day so if I get a lens with problems I might get stuck with it for a long time: so, thank you very much guys for providing me with such an incredible amount of empiric, real world data on these - I really appreciate it a lot.
Tim, did you consider the Zeiss 35 f.14 or 35 f2? I tried them both briefly, and it seemed to me that there is a lot of character in the f1.4 - however, I didn't have time for a thorough test so I decided to keep my Nikkor instead.