ecka said:
My missing Art lens list is:
Sigma 12mm f/2.8 DG ART
Sigma 20mm f/1.8 DG ART
Sigma 24mm f/1.4 DG MACRO (1:3-ish) ART
Sigma 85mm f/1.4 DG ART
Sigma 135mm f/1.8 DG OS ART
Sigma 100-300 f/4 DG OS ART
The Sigma 100-300 f/4 DG OS ART is an interesting option. I have the old one, but it is the worst lens I have and the only one of my lenses I would prefer not to buy. It is capable to give very good results. Sometimes... Look at any birds on my website:
www.len-lex.com/gallery.asp - all ware taken with that lens. But sometimes it just keeps failing. E.g. I shoot in good light from tripod with remote release and fine-focusing with liveview, fast shutter, no wind or earthquakes, but the result is damn blurry! Very inconsistent. Maybe it is just a bad copy. Anyway, with current level of Sigma's lenses it is very interesting to see such lens reworked. And OS would be a very useful thing on it. Kinda love and hate story, which probably would be better with the renewed version

And if we speak about birding – 100-300 is too short actually. Even with TC x1.4. So the rumored 300-600mm f/? OS Sport would also be interesting. I hope it will be constant f/4. It is not an easy task, but really isn't something impossible for Sigma. What I would be even more interested to see is a refresh of their super-telephoto primes! I do hope one day to get something like 500mm f/4 IS, but Canon's options are insanely expensive. Something IQ-comparable from Sigma for half the price and I'm in!