Just purchased at a good price a Sigma 24-105 f4 Art intending to sell it on for a profit. Testing it out on the D810 the pictures were rubbish even at F8. I set the Fine Focus adjust at 105mm but was not impressed. then I investigated the dock and watching u tube it looks like the required fine focus setting (16 of them) are all over the place from -17 to 0 through the focus range. So anybody got an ART lens and was it rubbish until you used the dock? Not sure weather to send it back ..the seller knows jack shit about cameras. You would think it would come out the factory so you could put it on zero and it would work but it seems not ..am I right? MORE THOUGHTS. When you have set a series of Fine focus settings using a dock is the lens computer causing the camera to swing its FFA settings or is it done in the lens and the camera sits at 0. This would be important if you wanted to use a D5300.
Will ring Sigma on Monday and ask wtf is going on.