Now, before i get the "hellraiser" stamp on me, just continue reading
I recently got an used DA 70 at a very good price.
Before we contionue we have to seperate two things. With "focus barrell" i mean the lens group assembly. Not the
focus ring barrell
My sample has an wobble that isnt very much, but its audible when handling the lens of camera. Sounds like something is loose. So i had a closer look myself!
Now, i dont recomend anyone to do this. I didnt even bother to take pictures because i had to focus on what i was doing
The focus barrell lens group of the DA 70 is designed to take out as one whole piece, there is no point going in from the front, that only reveals the front element.
I went in from the back taking of the black plastic cover, mount, contacts (not very fun to do), aperture control.
Looking at the back i now had a very nice view into the whole lens. I noticed that on each side of the lens group there was two small L-shaped metall parts with the long ends running between the lens group thread (cutouts in the thread) and focus ring thread. They hold the lens group into its non rotating position. Removing these makes it posible to rotate out the lens group.
Now with the lens group out of the lens house the thick threads on its outside is visible, and looking into the lens house itself one can see the corresponding threads that is part of the focusing ring.
This was what i was curious about! Was anything in there loose?
The threads on the inside of the lens house is made in one piece with the focus ring, so if the focus ring has no wobble, you dont need to worry, and dont need to do stupid things like i do
If the lens group falls out of from the house, those L-brackets has loosened (that has happened to some)
So, the "lens group barrell wobble" can only depend on ONE thing only.
And that is tolerance in the focus thread of both lens group part and focus ring part.
My sample is quite loose, and some others have thight ones. In my sample there is no grease or anything in those threads. I guess that would be the only way to make the lens group not to wobble. Or get another one....
Now your are thinking, "i could have told him that", but in the other posts about this i see people saying "Send it in, mine is tight", "Its normal, mine has a wobble to" and "All lenses wobble to some degree". So i just decided to look for my self!
Thats all. If you buy a new one that has wobble, request a new one! I would!