There are cheaper out there - I looked at a firm in East Sussex who advertise on the well known *bay - D70 conversion - £150. I was interested so I spoke to them and their engineer - I asked do you reset the autofocus for IR - reply - no need you just stop down to f8
! Spoke to ACS - yes they do reset the autofocus. They referred me to this site
http://diglloyd.com/prem/prot/DIP/publish/lenses.html
which is superb for those who wish to know about IR.