DotTune: AF tune technique without taking photos

Thanks for the link Craig. In their method you have to watch the distance scale indicator on the lens to know when focus mismatches from LV, because unfortunately Canon doesn't provide a digital rangefinder on their bodies. Watching the distance scale works well for lenses with a long focus travel for the subject distance being tuned, otherwise it's hard to discern movement, requiring going back into LV and checking the on-screen pattern again. I used the distance scale a lot when I was fighting the D800's Left AF issue.

Edit: Another issue is that the method presumes the PDAF system wont engage the AF if the camera thinks the subject is in focus. I'd have to check on my Canon bodies but with my D800 the PDAF will still nudge the lens back and forth for each PDAF acquisition even when the lens is at critical focus, and even in AF-S mode.