Originally posted by JimBrennan Hi Beholder,
I also have this lens, and was wondering what settings do you most often use for auto focus? I have become frustrated, so I just use the back button focus with the shutter button focus control shut off.
There is little special I could tell you. I mostly use it for people / portraits and I find all non macro screw drives to be fast but not ultimately precise when used on FF and with very wide apertures and when you inspect the result from 36 MPx. I guess it is about the gears in there and the precision of feedback the older lenses can provide. So I restrict myself to AF.S scenarios where the subject is not in motion.
Back button focussing to keep the autofocus system thinking about what it sees is a good safeguarding option.
It is also important to understand that - as this is a people lens - human faces actually provide rather poor contrast edges (baby faces are worst). Combined with minimal Dof and 36 MPx pixelpeeping will always create a lot of suboptimal results. So just take some more shots using the af-on button and don't worry.
Still this lens in my practise wins over the HSM driven Sigma 85/1.4 in a 9:1 ratio, simply because large clunky primes are not really attractive to pick when you leave the house.