dansclic: High quality at moderate prices ???? I Am dead !!!! If you want quality you have to pay for, cheap stuff from sigma is not a good deal : 50 per cent is decentered, mecanical problems, un reliable autofocus.....So again a 1700 USD Lens and what ? Buy a used nikon or canon instead.
Sigma lenses so far (for Canon 1DsII and 5DII):15mm f/2.8 fisheye: Fine.12-24mm f/4.5-5.6: Fine.20mm f/1.8: Required tape on the hood to avoid ratteling.28mm f/1.8: Fine.70mm f/2.8 macro: Sharpest lens ever encountered.100-300 f/4: Fine.So except for the tape on the 20mm hood (just like the Canon 200mm f/1.8!) no problems at all for 6 lenses.
Adler1970: I explain to you what kind of digital DSRL revolution was created by Nikon, with the D800:
Until now, the lenses were superior to the sensor. The sensor had to run behind the lenses. And these lenses were out of breath. But now, WIHT NIKON D800, the lenses are running out of breath behind the sensor. Now, the sensor is more advanced than any lens. This is a revolution, this is the uterus of a new generation of LENS, of a new generations of fotos, of a new vision, of a new GRAPHICS, of new corporate identity and corporate design.
That is BIG words, when the linear resolution increase from 5D3 to D800 is only 28%. I can assure you that lots of lenses will easily outresolve the D800 in the center. Not withstanding that the Nikon D800 is an impressive camera (I hope Canon makes something similar soon) I find it ridiculous to belive that going from 22 to 36 MP suddenly steps over a magic border which no lenses can cross...
Not the worlds first 180mm f2.8 macro - Sigma made one earlier, in the 1990's, also with AF. So it is kind of a revival.
J.K.T.: I simply can't figure out what is the point of having both this and 150/2.8 OS.
Just like what's the point of having both a 24 and a 28mm in the catalog. Choice. I have the Sigma 70mm macro, the 150mm would complement it nicely, someone having a 100-105mm might find the 180mm a good second longer macro.
Not the first time Sigma had a 180mm f2.8 macro though, so it's kind of revival, with all the modern additions of course.