Just spent an hour or so micro adjusting the focus on my Sony a900 with a Sony 70-300mm G SSM lens. It's the first time I've found a lens that needed it and the process took sometime before I was happy with the setting - turned out to need +13. Having done it once I think I'd find it quicker if there's a next time. Case of understanding just how much or little the increments from +20 to -20 change the focus point. There must be many camera/lens combinations in use that are not optimal in this regard. I imagine many folk are getting sub-par results without realising. I wonder also if reviewers ever check the equipment for back/front focussing before testing?