I use the Nikon 105mm Macro quite a lot and have noticed lens detect difference between the latest version of ACR and LightRoom 4.2 (RC). LightRoom automaticaly detects the lens whereas ACR does not and have to select the camera maker for it to detect the lens. Is this normal behavior?
Are you using ACR 7.1 RC or something earlier?
ACR should sucessfully choose and apply the correct lens profile for Nikon lenses. Have you modified your files at all before bringing them into ACR? Also, what is the behavior you are observing with older versions of ACR (please specify which version of ACR you have used before as well)?
Nope in fact it was a clean install of Photoshop CS5 with the latest and greatest ACR 6.7 final release. These files totally virgin NEF's straight from the camera
Update,the problem was ocurring in ACR6.7 Release Candidate and works in the final release...So problem solved