Quote Originally Posted by Black_Dog View Post
I've seen some videos on YouTube that show how you can do this yourself. It involves taking the dust ring off the front of your lens and manually adjusting the position of the front glass element (it is mounted on threads on the inside of the barrel and can be screwed in or out), which is basically what CPS would do if you send your body and lens into them. I have never tried it.
???

I don't think that's how CPS calibrates focus... The front element isn't generally the focusing element/group. Also, not all lenses are constructed that way - for some, the front element is glued in place, so 'unscrewing' it would be a bad idea.