I am sure I am not the first to do this but I don't recall reading it elsewhere. A quick and easy way to check and adjust your afma is: put the camera on a tripod or on a table and focus on a target using live view (make sure to turn off "enable continuous focusing" in the live view options). look at the focus scale setting. now switch off live view and focus again. you don't need to look through the viewfinder of anything just make sure the camera doesn't move and keep watching the focus scale on the lens. If it moves to a closer point it is front focusing, a farther point back focusing. do this a few times to make sure the results are consistent then adjust afma accordingly. When you have it adjusted to where the focus scale setting stays in the same place when switching between live view and normal focusing then your afma is right on. This is a really good way to quickly check make adjustments at different focal lengths and distances.