I prefer to use manual focus at all times. Given that the lens also has a predominant motorised focus system within it, is shimming likely to be beyond the capabilities an 'the ordinary man on the street' such as myself and require a technician's services ?
Whilst I have sorted out manual lenses over the past 40 year in photography, I've not worked on a motorised lens previously.
As the focussing ring is solid I was anticipating that I might have to remove the front decal to reveal any securing screws, but regrettably I am currently at work and will not be able to check this out until tonight.
Having never used this website before I don't know if the thread will expire when I log off or whether I can save it and continue tomorrow. If the former please confirm and I will rate your services for you and quit, if the latter I will advise my findings tomorrow.
Either way, you have my e-mail address I think.