Originally posted by dlh So, I manufactured a calibration tool of sorts, and took about sixty shots, varying the fine adjustment number every three shots or so, using only "live view" autofocus. Distance, about 41'. Results were all over the place. Extremely inconsistent. Finally got the best one I could get with that method (by the way, I was shooting with the camera sideways, and didn't bother to realign the image because the ruler's easier to read that way - the 24" mark is exactly even with the point of focus, and the 2x4 stud is eight feet long with approximately one inch increments).
The first of these is with manual focus (generally my preferred method), and the second w/LV-AF is using an adjustment value of +4:
That calibration tool should work just fine. One suggestion: shift the ruler down so that the middle of the rule lines up with center point of one of those circle targets. The aim of this is that when you shoot, you can validate the following:
- if the number (on the ruler) directly inline with the target is the sharpest, then no adjustment is necessary
- if the number (on the ruler) directly inline with the target is blurry and a number above it is sharper, that would mean the lens/body combo has back focusing
- if the number (on the ruler) directly inline with the target is blurry and a number below it is sharper, that would mean the lens/body combo has front focusing
I would not use liveview. I would use your viewfinder and center point to target. I would also use your camera's Auto Focus as that is the mechanism you are trying to resolve, not the manual focus.
Review on screen to confirm front or rear focus, then take multiple shots at different AF adjustment points (remember the order in which these are performed). Review on screen to find the best value.