I just recently upgraded my d70 / d50 combo to a dual d80 setup, and I could not have been happier! I got a real deal on the d80's, and they are definately a step up until I can afford a d700/d300 combo in the next few years. But when I started playing around with my Sigma 30 1.4, I realised that it couldn't ever lock focus on anything! It couldn't even lock focus on a black line printed on white paper! The focus shifts back and forth, never locking on as if it were searching for focus.! I emailed Sigma customer support, but they haven't responded.
According to another individual somewhere out there on the WWW, there is a problem with d80 bodies and the sigma 30 1.4. What a bummer, as this was my favorite lens and the only 1.4 lowlight lens I could possible afford.
The lens can still obtain a few keepers that are spectacular, but I have to take multiple shots to get those keepers, and I have a wedding coming up in 2 weeks that I really hoped I would have this lens for.
Anyone else ever have to deal with this? This is like a greek tragedy for me!
I would press on with Sigma and see if there is a fix (don't email... that's the black hole of customer service - it makes them think you don't really care).
Customer Service Department call toll free (800) 896-6858.
I should have never picked up my pals d3, I am now spoiled forever for anything less!