Cue alignment update - visual perception error/distortion of the line of aim

z0nt0n3r said:
i don't have pool balls in my home, i only have a crystal ball which is almost the same size and shape as a pool ball, so maybe i can use it with the laser to locate center ball but i'm not sure if it's ideal.i will have to take the laser at a pool hall in order to do the other alignment tests that you are doing.

one other question, when you were doing the laser alignment tests, did you find that with the wrong head positions the cue was ending up slightly off the line and you had to make small bridge-back hand adjustments to get the cue online? and with the correct head position did you find that the cue was automatically ending up online without too many micro-adjustments?this is the only explanation i can think of about why you made the conclusion that a certain head position is better than the others and i'm coming to the same conclusion myself.i'm sorry if i have asked you the same question in the past, i just want to be sure.
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I have to say again that I'm not an instructor but I can give my own experience. I don't buy into the idea that there is a "vision center" that makes everything perfect. If I were to do it over again as a beginner I would choose a head/eye position that came naturally and then I would work on where the cue needs to be for a straight cue delivery. That cue alignment might not (probably won't) feel right at first, but soon enough you will learn what a straight stroke should look and feel like from that vantage point. In Mark Wilson's book he kind of says as much when he says you can put your head wherever you want so you might as well just center the cue under the chin between both eyes. I don't do it that way but the idea is similar.

I have a pretty consistent head position from a long time of play so I can't really comment on your situation other than to say if you get down on the shot in different places each time that sounds like trouble. Also, when the laser is on the ball you can easily place the tip in the right spot (on the laser line) so it's hard to say where you would have placed it if the laser line weren't there. You'd know if there was a way to turn the laser line on after you get into position.
 
Dan White said:
I don't buy into the idea that there is a "vision center" that makes everything perfect. If I were to do it over again as a beginner I would choose a head/eye position that came naturally and then I would work on where the cue needs to be for a straight cue delivery.
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Is that also where the cue needs to be for things to "look straight"? If so, what's the difference between that and your "vision center"?

pj
chgo
 
Patrick Johnson said:
Is that also where the cue needs to be for things to "look straight"? If so, what's the difference between that and your "vision center"?

pj
chgo
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I know your definition of vision center is something like "wherever your head ends up when the stroke is finally straightened out" or something along those lines. I'm saying that finding your "vision center" where the aim looks good does not guarantee that you are, in fact, lining the cue up properly. I set out at one point to find that set up where the shot would look correct and the aim would also look/feel correct. I did find that configuration but I looked like a pretzel trying to shoot a ball. For 30 years I placed my head where it felt correct and natural. Problem was it was NOT correct. My conclusion is that stroking the cue straight might not feel correct at first, especially if you have developed a bad habit, but eventually the stroke will feel right. I could have kept shooting with my head where it was for 30 years and forced my stroke on the correct line but when I tried that it felt completely wrong and I abandoned it. Through the journey I took I ended up with a very different head position but with a stroke that is correct.

I'm writing this kind of fast so I don't know if I answered your question. In a nutshell, I'm saying that there is not necessarily one specific head position ("vision center") where the stroke must necessarily then fall in line simply because you are on that spot visually. Additional work is needed to make sure the cue is actually stroked on the shot line. For me, it was not practical to maintain a visual that felt normal and still be able to stroke the cue straight. I had to abandon my "normal" vision center in order to have a stance and stroke that felt doable.
 
The whole 'vision center' concept is flawed. I've been trying to explain that to you guys for a long time now and you systematically ignore me. If you think you can resist the pull of your PHYSICALLY dominant eye, you are greatly mistaken. Instead of fighting your dominant eye, go with it and make whatever aiming adjustments you need to make --- the way athletes do. Otherwise you will find yourself constantly fighting your natural tendency towards your dominant eye. Fighting your physicality will tire you out sooner because it requires constant attention and diligence. And believe me, you won't always be that diligent and your cue will naturally drift under your dominant eye.
 
Dan White said:
I have to say again that I'm not an instructor but I can give my own experience. I don't buy into the idea that there is a "vision center" that makes everything perfect. If I were to do it over again as a beginner I would choose a head/eye position that came naturally and then I would work on where the cue needs to be for a straight cue delivery. That cue alignment might not (probably won't) feel right at first, but soon enough you will learn what a straight stroke should look and feel like from that vantage point. In Mark Wilson's book he kind of says as much when he says you can put your head wherever you want so you might as well just center the cue under the chin between both eyes. I don't do it that way but the idea is similar.

I have a pretty consistent head position from a long time of play so I can't really comment on your situation other than to say if you get down on the shot in different places each time that sounds like trouble. Also, when the laser is on the ball you can easily place the tip in the right spot (on the laser line) so it's hard to say where you would have placed it if the laser line weren't there. You'd know if there was a way to turn the laser line on after you get into position.
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it sounds to me that you just straightened out your stroke and your problem had nothing to do with wrong head position. some coaches say that cueing across the ball causes you to aim incorrectly and also the opposite, aiming incorrectly causes you to cue across the ball and probably for you, the first one was the problem.
 
z0nt0n3r said:
it sounds to me that you just straightened out your stroke and your problem had nothing to do with wrong head position. some coaches say that cueing across the ball causes you to aim incorrectly and also the opposite, aiming incorrectly causes you to cue across the ball and probably for you, the first one was the problem.
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I'm not sure how to categorize the problem. I used to get down on the shot wherever my eyes told me to and everything looked perfectly lined up. In fact, the cue was cocked too far away from my body and the tip was a tad left of center (I'm a lefty). The shot would go in because I found on video that at the back of the stroke I was pulling the cue in toward my body about a quarter inch to get on the correct shot line. I must have learned to do this unconsciously over time in order to pocket the ball. I suppose I could have ignored that but my shot making was not where I wanted it to be so I worked to eliminate that.
 
FranCrimi said:
The whole 'vision center' concept is flawed. I've been trying to explain that to you guys for a long time now and you systematically ignore me. If you think you can resist the pull of your PHYSICALLY dominant eye, you are greatly mistaken. Instead of fighting your dominant eye, go with it and make whatever aiming adjustments you need to make --- the way athletes do. Otherwise you will find yourself constantly fighting your natural tendency towards your dominant eye. Fighting your physicality will tire you out sooner because it requires constant attention and diligence. And believe me, you won't always be that diligent and your cue will naturally drift under your dominant eye.
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I agree with you about the vision center. I think things are more complicated. That is a little different from the pull of the dominant eye subject, though.

I know we've discussed this before. I changed my eye position from the inside corner of my left eye (where it was for 30 years) to inside corner of my right eye. If I now just pick up a cue cold and get down on a shot without thinking about anything and line up a shot I will automatically line up under the corner of the right eye. It just looks "right" to me now because over time the positive reinforcement of having successful shots tells me to get down on the shot this way, I guess. It sounds like you disagree with Mark Wilson on this. It seems to me that a player might drift back to "natural" if they haven't fully gotten used to a new head position. I even tried once to go back to my old head position. I didn't like it and I figure what's done is done. I'll just get down on the shot wherever I naturally go now and work from there. Corner of the right eye is the "natural" spot for me now. I don't know how the brain works so I can't say why that would be.

I can say that having the dominant eye off to the side more than I used to did affect the direction of my stroke at first. When I went forward with the cue I tended to want to move the cue to being more under my dominant eye. This was such a small thing that you can't see it but you can feel it. I only found it by using the laser and seeing that my follow through tracked in that direction. One caveat, though. In my old head position when I would hit a straight follow shot the cue ball would follow to the right 90% of the time. That is the same problem that I found with the laser so in reality I was doing the same thing in both eye positions. Then add the other variables like grip pressure and transition problems and the issue becomes clear as mud.

I keep an open mind on these things because they are complicated and I respect your opinion on things as you've walked the walk. I can only say what my own experience is over many years, and while I keep what you are saying in the back of my mind as something to look out for, I have to say I find no tendency for me to line up under my old dominant eye position.
 
Dan White said:
I know your definition of vision center is something like "wherever your head ends up when the stroke is finally straightened out" or something along those lines.
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It’s wherever your head, stick and the rest of your stance are when stroking straight and online looks straight and online.

pj
chgo
 
Patrick Johnson said:
[Vision center is] wherever your head, stick and the rest of your stance are when stroking straight and online looks straight and online.
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Dan White said:
What if there is no position where all of those requirements can be met?
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Then I suppose it's whatever stance (including head & stick position) works best for you. In other words it's results based, not a strict physical definition.

To get my stick under my eyes just right and have a reliably straight stroke along my line of sight, I had to twist my shoulders and torso a little and consciously place my elbow in position. It was less natural/comfortable for awhile - but I got used to it.

pj
chgo
 
Patrick Johnson said:
Then I suppose it's whatever stance (including head & stick position) works best for you. In other words it's results based, not a strict physical definition.

To get my stick under my eyes just right and have a reliably straight stroke along my line of sight, I had to twist my shoulders and torso a little and consciously place my elbow in position. It was less natural/comfortable for awhile - but I got used to it.

pj
chgo
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I read Dr. Dave's section on vision center and he also seems to say (without actually saying it) that what is your "natural" eye position is not necessarily correct. I would agree with that part, which I think is what Fran disagrees with. I think he goes a little too far with the vision center as the "be all, end all." I'm having trouble expressing my problem with the vision center concept, but it seems to be one of those ideas that sounds good but we don't really know if it means anything. Where did the term "vision center" come from?

Let me give an example: In Dave's discussion he says that you can find your vision center if you put an ob in the jaws of a corner pocket, the cb at center table, and then you can lay the cue down in line with those balls so that everything is lined up. I did this to the best of my ability and then I took my laser and shined the light over the two balls at the centerline, of course. The question is whether the cue is really lined up or not. The cue tip was right on the line but the butt of the cue was a full quarter inch off! You aren't going to make many shots with the cue off 1/4 inch. When I pick up the cue and get into shooting position I had the cue up to the grip hand right on the line. That is because I learned what it looked and FELT like to be on the shot line while in the shooting position. So to me this exercise in finding the vision center is of limited use, maybe only to rank beginners.

If "vision center" means do whatever you have to do to have a perfect stroke then it has no real value in helping you get there. If, on the other hand, "vision center" means that if you put your eyes in position x then that is a prerequisite to achieving a straight stroke, then there is value in that. I just don't see any indication that this is true, which is why I asked about the origin of the term.
 
Dan White said:
If "vision center" means do whatever you have to do to have a perfect stroke then it has no real value in helping you get there. If, on the other hand, "vision center" means that if you put your eyes in position x then that is a prerequisite to achieving a straight stroke, then there is value in that. I just don't see any indication that this is true, which is why I asked about the origin of the term.
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I don't think "vision center" has anything to do with defining or prescribing a straight stroke. It's about how you align your eyes with your stick/stroke, assuming it's in line with the shot.

pj
chgo
 
Patrick Johnson said:
I don't think "vision center" has anything to do with defining or prescribing a straight stroke. It's about how you align your eyes with your stick/stroke, assuming it's in line with the shot.

pj
chgo
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i have only superficially read thru this thread
sorry
heres my 2 cents
if you want to test if you have a straight stroke
place a ball on the spot or a donut reinforcer
shoot straight at something but close your eyes after address and before your backswing
after your stroke open your eyes and see if your cue is over the center of the spot or reinforcer
if it is your stroke is straight.... :)
now put a ball on the spot or reinforcer and aim straight at something
look at the cue ball
are you on the vertical axis?
if yes shoot
does your cueball have spin?
if yes
what you see as center ball is not center ball
thats where your head position comes in to play to find your vision center
jmho
icbw
 
there is more to it when you want to hit an object ball perfectly in the center with no spin
ie
the PERFECT stop shot
 
bbb said:
there is more to it when you want to hit an object ball perfectly in the center with no spin
ie
the PERFECT stop shot
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I've been practicing straight and near straight shots lately. Follow/draw/deadball/airball... what I've achieved so far amounts to improved jargon ie. "zeroing out" my stroke. Seems I require a specific bridge height, backhand elevation, and stroke speed to up the odds to "occasionally". There is so far, no flex on the sweet ratio. I feel like struggling with it for a while.
 
Dan White said:
I agree with you about the vision center. I think things are more complicated. That is a little different from the pull of the dominant eye subject, though.

I know we've discussed this before. I changed my eye position from the inside corner of my left eye (where it was for 30 years) to inside corner of my right eye. If I now just pick up a cue cold and get down on a shot without thinking about anything and line up a shot I will automatically line up under the corner of the right eye. It just looks "right" to me now because over time the positive reinforcement of having successful shots tells me to get down on the shot this way, I guess. It sounds like you disagree with Mark Wilson on this. It seems to me that a player might drift back to "natural" if they haven't fully gotten used to a new head position. I even tried once to go back to my old head position. I didn't like it and I figure what's done is done. I'll just get down on the shot wherever I naturally go now and work from there. Corner of the right eye is the "natural" spot for me now. I don't know how the brain works so I can't say why that would be.

I can say that having the dominant eye off to the side more than I used to did affect the direction of my stroke at first. When I went forward with the cue I tended to want to move the cue to being more under my dominant eye. This was such a small thing that you can't see it but you can feel it. I only found it by using the laser and seeing that my follow through tracked in that direction. One caveat, though. In my old head position when I would hit a straight follow shot the cue ball would follow to the right 90% of the time. That is the same problem that I found with the laser so in reality I was doing the same thing in both eye positions. Then add the other variables like grip pressure and transition problems and the issue becomes clear as mud.

I keep an open mind on these things because they are complicated and I respect your opinion on things as you've walked the walk. I can only say what my own experience is over many years, and while I keep what you are saying in the back of my mind as something to look out for, I have to say I find no tendency for me to line up under my old dominant eye position.
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Dan, the degree of eye dominance does affect the pull. Inside corner is pretty close to the center. You may be one of the lucky ones. But you'll still have to see how things progress over time. Some players have a very strong dominant eye, and you can see it where the cue is clearly placed under the center of that eye. Out of all the players who place their cues directly under their dominant eye ---- if they were to do that so-called vision center calculation, how many of them do you think would wind up with the cue centered under their dominant eye? Yet, that's how they shoot ---- particularly the professional snooker players. They've made their aiming adjustments.

I also want to mention the role of eye pathology in all of this. The player may have to force the issue of placing the cue away from the dominant eye if they can't visually see well out of the dominant eye. There's no guarantee that the dominant eye sees clearer than the recessive eye. I'm not referring to seeing the line correctly. I mean simply seeing clearly.
 
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bbb said:
i have only superficially read thru this thread
sorry
heres my 2 cents
if you want to test if you have a straight stroke
place a ball on the spot or a donut reinforcer
shoot straight at something but close your eyes after address and before your backswing
after your stroke open your eyes and see if your cue is over the center of the spot or reinforcer
if it is your stroke is straight.... :)
now put a ball on the spot or reinforcer and aim straight at something
look at the cue ball
are you on the vertical axis?
if yes shoot
does your cueball have spin?
if yes
what you see as center ball is not center ball
thats where your head position comes in to play to find your vision center
jmho
icbw
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There are many possible reasons why a player isn't shooting straight. Doing that 'vision center' calculation will only serve to complicate things for the player who may have a severely dominant eye. It won't work over time. The player's cue will slowly start to drift back towards their dominant eye. It's physical. Can't be helped.
 
If players with a severely strong dominant eye did that “vision center thing”
I bet you would find they would end up with the cue very close to under their severely dominant eye.
fran you are such a great instructor
why are you so resistant to the concept of the vision center ?
 
Neither the stick nor the shot care what you are looking at. Further, I think stereo vision will only allow one plane of coherence for a given focal distance and only directly in front of your face at that. Attempts to resolve in the periphery will yield imagery that is not geometrically coherent to the straight ahead view and that, with perfect eyes - at that. (yeah I writed that) I'm working on setting the stick first and then shooting per that setting. That does seem to be the way to go.
 
straightline said:
Neither the stick nor the shot care what you are looking at. Further, I think stereo vision will only allow one plane of coherence for a given focal distance and only directly in front of your face at that. Attempts to resolve in the periphery will yield imagery that is not geometrically coherent to the straight ahead view and that, with perfect eyes - at that. (yeah I writed that) I'm working on setting the stick first and then shooting per that setting. That does seem to be the way to go.
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What happens if you can't set the stick directly on the shot line? When I did it "by eye" I was off 1/4" at the butt - unacceptable. You might want to draw a straight line diagonally across the table or use a laser or find some other means to assure the ob/cb/stick alignment is straight. If you don't take extra caution then you are training yourself to line up crooked.
 
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