fcotterill
Well-known member
This is very similar to the method I use, and with a steel engineers ruler inclined to reveal Front or Back focus. Adjust the focus offset in the menu setting accordingly...To test a lens for AF fine tune, I use this homemade set up. Works a treat. Focus on the bar code, then you can see if the lens is back or front focusing by looking at the rule that is on a 45 Deg angle.
This was my F mount 105 f1.4E on my D850. As you can see, it was spot on.
Close up
It's simpler and faster than the textbook tedious AFFT mean of averages method. It doesn't need a heavy 100% vibration free support.