We've discussed this before but haven't seen eye to eye on this. I'm probably not making my point very clearly. Let me try it this way: When many of us started playing we simply got into shooting position where the shot looked AND FELT straight. I add "felt" because you can't see much of the cue and your grip hand while in shooting position so however you end up down on a shot that is what looks and feels straight to you naturally. This may not in fact be a straight alignment and a course correction would be needed mid stroke ala Bob Jewett's demonstration where he swoops the cue to make it straight. So what does that mean? It means that you need to get an independent confirmation from a friend or laser that the ob/cb/cue/grip hand and arguably the upper arm are all on the same line while you are holding the cue. Once you get that confirmation you can now see if you can move to a position where that confirmed straight LOOKS straight. Here's the point: once your brain has decided that crooked looks straight, there is not necessarily a new head position where this new straight looks straight and you are able to get into shooting position.If crooked looked straight then by definition it wasn't your vision center. That's where straight looks straight.
I recall when my father looked down my cue and kept telling me to move the cue over a little more... a little more. When it was straight he said STOP, PERFECT. I asked him if he was on drugs because there was no way that was straight. My brain had become used to a crooked alignment and considered it to be straight. The real straight line did not look straight to me no matter what, unless possibly if I had gotten out of shooting position and then crouched down to look down the cue, but there's no point in that. The solution for me was to retrain my brain as to what straight was. It involved trusting that I was really straight even when it didn't look like it. I had to switch from left eye to right eye in order to get my arm in line with the cue and I had to trust the shot. Positive results and time resulted in a new, straight alignment in which there is no swoop in my stroke due to perception issues (hand/wrist issues are another story).
What is the point in the concept of "vision center" for many players where there is no "straight looks straight" while in shooting position? Think about it. In Dave's video he and Bob agreed that Bob has been playing with a crooked set up for so long that it wasn't worth training him to do it right. That's not because his arm won't swing straight it's because he can't see straight as straight and would need to retrain his perception to make straight work.
Then there are professional instructors who do not subscribe to the vision center concept. I'm just saying the idea isn't completely fleshed out for anyone but possibly rank beginners.
Not when your brain has already been trained to see a crooked shooting set up as straight. I would love to ask Bob to align his head where straight looks straight and see if he could then move the cue without poking himself in the back or leg. It takes time to relearn straight, which means 'vision center" doesn't have much meaning to such a person.I think pretty much anybody, after positively determining their stick is "straight", can find the head position over it where it looks straight(est). That's all the vision center concept is - probably the best place to start training your perception.
pj
chgo
I haven't made a career out of studying all of this stuff, so I don't have all the answers. I'm just saying things are more complicated than just "vision center, vision center."