Within all things there are variances. The closer the tolerance range the more things cost. So does this fall within the normal parameters of this camera and lens? He did not cover any of the other focus points so there is no comparisons to be made.
Why test at 5 feet? How often would you use a 50mm lens focusing at 5 feet?
Would he use or you use AFS or AFC Single Point for most shooting situations? How would the other focusing modes work?
Considering the DOF for a 50mm focused at 5 feet with an aperture of f/1.4 is 3", is the almost 1" variance out of tolerance? Could the lens fine tuning be set to provide a closer tolerance?
What would the results be if he tested at 8 feet?
What a nice opportunity to show how valuable a product is? Is it a test worth merit or an opportunity to help bolster sales? Too many questions.
If he intended to test the AF, he didn't design the test properly. Lenses have field curvature, especially fast lenses like the 50/1.4 he used. He used the focus point on one end of the frame, and then reviewed the DOF at the center of the image. The shift in DOF can be the result of field curvature, or of an AF issue, or both. With his test, it's impossible to say. To check AF, one needs to look at the DOF in the neighborhood of the AF point.
I noticed that and wondered why he was doing his test in a way that introduced variables that would swamp the sought after effect in most lenses except for macros which tend to have flat focal fields. His test only increased confusion. The test for the reported problem is simple enough, look at focus accuracy immediately around the focal point used and ignore the rest of the frame. Change focal points to the center and look only right around that one and note any change in focal plane in relationship to the particular featured focal point. It took a bit of testing to find it in the first place but if tested incorrectly as the video portrayed, almost any lens and camera combination would reveal a problem that is not due to AF problems. Stan St Petersburg Russia