Crooked Pro Pool Strokes in Video

dr_dave · Jan 22, 2020

Check out the following new video:

NV J.36 – Crooked Pro Pool Strokes in Video

It is a follow-up to the following two recent videos that generated many comments on AZB, YouTube, and Facebook concerning the apparent crookedness of Samm's stroke during one of the shots:

NV J.33 – Top 10 Secrets of a Good Draw/Backspin/Screw-Back Shot
NV J.34 – Is this Stroke Crooked … or is it Parallax?

Check out the new video. I think it finally provides totally clear and convincing evidence to explain and demonstrate the optical illusions that can occur with video camera perspective and parallax effects related to an elevated cue or a cue that changes elevation during a shot (e.g., as with a pendulum stroke).

Enjoy,
Dave

asbani · Jan 22, 2020

By crooked stroke, do you mean the line of the cue only, or do you mean the pro elbow + arm line? I just want to be clear about this.

dr_dave · Jan 22, 2020

asbani said:
By crooked stroke, do you mean the line of the cue only, or do you mean the pro elbow + arm line? I just want to be clear about this.

A stroke is straight if the cue remains in a vertical plane during the stroking motion. There are many variations of arm/wrist/hand orientation and motion that can create a straight stroke.

Regards,
Dave

asbani · Jan 22, 2020

dr_dave said:
A stroke is straight if the cue remains in a vertical plane during the stroking motion. There are many variations of arm/wrist/hand orientation and motion that can create a straight stroke.

Regards,
Dave

yea reminds me of Keith back in his days, his elbow looked to go sideways but his cue stroke vertical line is as straight as an arrow.

thanks for clarifying, so you were talking about the cue line itself, and I do agree then with the entirety of the video, people who don't know perspective will find it difficult to see this, all you need is a 3d visualization and to be good at figuring out perspectives.

dr_dave · Jan 22, 2020

asbani said:
... people who don't know perspective will find it difficult to see this, all you need is a 3d visualization and to be good at figuring out perspectives.

What about the Corey jump shot in the video? I don't think anybody would think that aim looks right, even with the best understanding of perspective.

Regards,
Dave

asbani · Jan 22, 2020

dr_dave said:
What about the Corey jump shot in the video? I don't think anybody would think that aim looks right, even with the best understanding of perspective.

Regards,
Dave

It looked straight to the shot to me, his elbow had to go sideway to be able to stroke it, but the cue line itself was straight to the shot, I do have good eye for 3d viewing.

dr_dave · Jan 22, 2020

asbani said:
dr_dave said:

What about the Corey jump shot in the video? I don't think anybody would think that aim looks right, even with the best understanding of perspective

Click to expand...

It looked straight to the shot to me, his elbow had to go sideway to be able to stroke it, but the cue line itself was straight to the shot, I do have good eye for 3d viewing.

You are saying that Corey's aim in the following video frame looks accurate to jump over the 7 and pocket the 6 in the bottom-right corner?

If so, I am very impressed.

Regards,
Dave

asbani · Jan 22, 2020

dr_dave said:
You are saying that Corey's aim in the following video frame looks accurate to jump over the 7 and pocket the 6 in the bottom-right corner?

View attachment 539578

If so, I am very impressed.

Regards,
Dave

Not from this camera angle that you posted no, if you look at this shot only by seeing this camera angle then you are right it is deceiving, but if you look at the whole picture, i.e. different camera angles etc, but I remember this match, when viewing with the default camera angle, e.g this one here (Attached below in the fig.) then it looks to me straight in there, and then seeing your posted camera angle I can distinguish the parralaxing issue and see how it can be straight to the 6 ball.

asbani · Jan 22, 2020

Here, I can see the stroke and the cue line is straight to the shot, the one ball, by Gorst, I seen that in your video when you draw the white line it goes away, but that's not how I look at it from 3d perspective, it is clear to me that the cue line going straight to the one ball, but I think your line is drawn as a 2d mindset which is how it can deceive.

iusedtoberich · Jan 22, 2020

Good topic. I'll definitely watch this one in full, later

As someone myself who has fooled around with cameras and pool quite a lot over the past 7 years, I have learned that you absolutely can't trust what you see on a video or photograph. Even a professional production such as Matchroom with a directly overhead shot has a lot of parallax (and probably other things beyond my optics knowledge) that can affect how the table layout is perceived. People online take as gospel: straightness of stroke, pocket size, pocket angles, symmetry of pocket angles, symmetry of slate opening relative to pocket facings, whether balls pass each other, angles of shots, etc, based on camera optics that are all over the board.

dr_dave · Jan 22, 2020

iusedtoberich said:
Good topic. I'll definitely watch this one in full, later

As someone myself who has fooled around with cameras and pool quite a lot over the past 7 years, I have learned that you absolutely can't trust what you see on a video or photograph. Even a professional production such as Matchroom with a directly overhead shot has a lot of parallax (and probably other things beyond my optics knowledge) that can affect how the table layout is perceived. People online take as gospel: straightness of stroke, pocket size, pocket angles, symmetry of pocket angles, symmetry of slate opening relative to pocket facings, whether balls pass each other, angles of shots, etc, based on camera optics that are all over the board.

I look forward to hearing any thoughts or feedback you have after you watch the video.

Catch you later,
Dave

Snooker Theory · Jan 22, 2020

Just watched, "NV J.36" very impressed, never had heard of that, although that explains when I watch pro's sometimes their strokes don't look straight, also when videotaping myself I will work to get the camera directly in line so as to not distort my perception.

dr_dave · Jan 22, 2020

Snooker Theory said:
Just watched, "NV J.36" very impressed, never had heard of that, although that explains when I watch pro's sometimes their strokes don't look straight, also when videotaping myself I will work to get the camera directly in line so as to not distort my perception.

I also notice the effect when watching students live (and on video). If I am not directly in front or directly behind the shooter, it is very difficult to verify center-ball alignment, aim accuracy, and stroke straightness.

I'm glad you liked the video,
Dave

straightline · Jan 22, 2020

dr_dave said:
I look forward to hearing any thoughts or feedback you have after you watch the video.

Catch you later,
Dave

It's said "The camera does not lie." it seems not to tell the truth either.

For arguments sake, is it possible Corey is "cutting" the cueball to some degree? Is that even possible? IOW if you chopped at the cueball with a hand held ball instead of a jumper, the shot would be actuated in the direction of ball alignment and not chop angle.

dr_dave · Jan 22, 2020

straightline said:
It's said "The camera does not lie." it seems not to tell the truth either.

For arguments sake, is it possible Corey is "cutting" the cueball to some degree? Is that even possible? IOW if you chopped at the cueball with a hand held ball instead of a jumper, the shot would be actuated in the direction of ball alignment and not chop angle.

The only way the CB could jump in a different direction than the cue is pointing at the brief moment of contact is if the CB is hit with sidespin, in which case the CB will experience a small amount of immediate swerve.

Regards,
Dave

straightline · Jan 22, 2020

dr_dave said:
The only way the CB could jump in a different direction than the cue is pointing at the brief moment of contact is if the CB is hit with sidespin, in which case the CB will experience a small amount of immediate swerve.

Regards,
Dave

Then given the shot in question is a jump, can the effect be pronounced enough to account for the Deuel shot? Regardless, the shot does play out as a normally struck jump.

dr_dave · Jan 22, 2020

straightline said:
dr_dave said:

The only way the CB could jump in a different direction than the cue is pointing at the brief moment of contact is if the CB is hit with sidespin, in which case the CB will experience a small amount of immediate swerve.

Click to expand...

Then given the shot in question is a jump, can the effect be pronounced enough to account for the Deuel shot? Regardless, the shot does play out as a normally struck jump.

Agreed. The shot is a normally-struck jump with no (or very little) sidespin. Even if he had applied a lot of sidespin, there is no way the CB could react as implied in the overhead view. The immediate swerve effect is very small. The illusion is due to camera perspective/parallax ... not pool physics.

Regards,
Dave

dr_dave · Jan 23, 2020

dr_dave said:
Check out the following new video:

NV J.36 – Crooked Pro Pool Strokes in Video

It is a follow-up to the following two recent videos that generated many comments on AZB, YouTube, and Facebook concerning the apparent crookedness of Samm's stroke during one of the shots:

NV J.33 – Top 10 Secrets of a Good Draw/Backspin/Screw-Back Shot
NV J.34 – Is this Stroke Crooked … or is it Parallax?

Check out the new video. I think it finally provides totally clear and convincing evidence to explain and demonstrate the optical illusions that can occur with video camera perspective and parallax effects related to an elevated cue or a cue that changes elevation during a shot (e.g., as with a pendulum stroke).

Enjoy,
Dave

I have noticed over the years that my tip sometimes finishes to the left of the line of aim after the follow-through, especially with fast-speed shots. I once thought it was due to the forward momentum of the cue twisting my stance slightly as the cue is slowed and stopped. But now I know the actual answer. I discovered it while filming my recent YouTube video. Here's are stills from one of the shots in the video:

Notice how my cue moves to the left of the shot line and then back, all after the hit. On fast-speed shots, sometimes the tip doesn't move back. Can anybody explain why this is happening? I know why. I just wanted to see if astute viewers out there can figure it out.

I'll post my answer after you guys take a stab at it.

Thank,
Dave

straightline · Jan 23, 2020

My take on this is STROKE. Every joint from the hips out is involved. All those micro angles and biases including your eyeballs and grey matter - matter.
I noticed in your video you and Ms. Diep have the same "left english" finish to the stroke. I attribute this to elbow alignment give or take the conditions offered above and elsewhere. I have the same affliction except the more common "right english" effect. This happens because in trying to visually square off to the shot, my elbow is progressively biased towards my navel. I use what is referred to here as backhand english so this inconsistency was pretty obvious and by no means an illusion. ie; pairaslacks error ...

Sigel stands way off to the side and displays no such stroke error. Maybe his neck suffers.

John Morra (righty) leans way over the stick. People have commented on dominant eye biases but I rather think it's more stroke. I used to shoot in this manner because it addressed the elbow to navel effect by beginning the stroke in closer proximity to the navel and more closely paralleling the spine.
It works very well on shots that require accuracy _and_ power besides being plain truer than my default approach.

Next...

dr_dave · Jan 24, 2020

straightline said:
My take on this is STROKE. Every joint from the hips out is involved. All those micro angles and biases including your eyeballs and grey matter - matter.
I noticed in your video you and Ms. Diep have the same "left english" finish to the stroke. I attribute this to elbow alignment give or take the conditions offered above and elsewhere. I have the same affliction except the more common "right english" effect. This happens because in trying to visually square off to the shot, my elbow is progressively biased towards my navel. I use what is referred to here as backhand english so this inconsistency was pretty obvious and by no means an illusion. ie; pairaslacks error ...

Sigel stands way off to the side and displays no such stroke error. Maybe his neck suffers.

John Morra (righty) leans way over the stick. People have commented on dominant eye biases but I rather think it's more stroke. I used to shoot in this manner because it addressed the elbow to navel effect by beginning the stroke in closer proximity to the navel and more closely paralleling the spine.
It works very well on shots that require accuracy _and_ power besides being plain truer than my default approach.

Next...

Have you seen this video:

NV J.35 – Top 10 Aim, Alignment, and STROKE DRILLS

Check it out and you will see that my stroke is usually fairly straight.

I would also consider the stroke in my most recent video straight. However, after the tip hits the CB (and near the end of the follow-through), the tip does move off line to the left and then returns to finish on the line (as shown by the video frame images I posted). This is what I am asking about. What is causing this? Sometimes, especially with faster-speed strokes, the tip does not return (although, the stroke into the CB is straight, with the CB heading in the intended direction).

Anybody else have an theories?

Regards,
Dave

Crooked Pro Pool Strokes in Video

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