Originally posted by SSGGeezer I am the second or third owner of mine and I have not had that issue, so I guess I have been lucky. if it totally gives up you can spend the cost of another used model to repair it or just use it as a manual focus lens. I would go that route if my SDM failed completely.
I have two copies of it and both had properly working SDM to begin with.
I had a second so my son could have one to use on one of my other cameras but he much preferred the HD 50-300 so the original one went unused for several months.
EDIT: Now not so sure on the timeline. Hmmmm....not important I guess)
Some time back I had grabbed it to use since it was more convenient at the moment and discovered the auto-focus wouldn't work. Fiddled with it for a minute or more and it suddenly worked. So I took it out again a few weeks later, same thing, very slow to wake but eventually it did tho somewhat inconsistent. Two weeks ago I tried it again and in a couple minutes of trying it never would wake. Nada. Of course the throw on it makes it super easy for manual focusing which I ended up doing.
I'll probably sell it priced as a manual lens, and who knows maybe with regular use it will come back to life tho I doubt it. Since I have another copy with proper SDM I won't bother holding onto this one. It's a great lens, especially so for portrait use, even if it won't auto-focus.