A WC Apologist's Stunning Blunder on the Backyard Rifle Photos and the HSCA PEP

[Mitch Todd]

Oh my goodness. I have never seen anyone try to bluff their way like you're doing here. Your statements seem to be deliberately misleading, unless you honestly do not understand plain English. I notice you have simply ignored the PEP paragraph that introduces what they call the measurements that determined the vertical parallax. This is a repeat of your stunning refusal to acknowledge Dr. DiMaio's plain English about the behavior of FMJ bullets.

Do you know what "vertical parallax" means? If the PEP were just introducing ratios, where is the vertical parallax? IOW, where is the difference between the 133-A and the 133-B "MEASUREMENTS" (the PEP's term) if it's not in the calculation that follows the paragraph? Where is it? Huh?

Vertical parallax is "the vertical difference between corresponding points in two images." It is not a ratio: it is a measurement that is reached after factoring the scaling distance to account for any differences in magnification.

Let's read the PEP paragraph that introduces the vertical measurements again:

Vertical parallax was calculated by measuring the vertical distance from the center of the dark horizontal object, which looks like it might be a gate bolt or latch, to the bottom edge of the screen of the screen door in the background.

Are we clear so far? They calculated the vertical parallax by measuring the vertical distance from the gate bolt to the bottom edge of the screen door. That is not a "ratio." That is a measurement, which is why they said they "MEASURED" the vertical distance to calculate the vertical parallax. You don't seem to understand what "parallax" means.

Let's continue as they explain that the scaling distance was considered to take into account the differences in magnification, so that the "MEASUREMENTS" were related to the distance from the left edge of one picket to the left edge of the next:

To establish scale, that is to take into account differences in magnification, these measurements were related to the distance from the left edge of one picket to the left edge of the next, measured in a horizontal direction. This scaling distance was measured on the two center pickets of the four that appear to constitute the gate at the level of the lower edge of the top horizontal member. The results are as follows: (6 HSCA 178-179)

"The results" for what? For the vertical parallax, i.e., the differences in the vertical distances between the measured objects in 133-A and 133-B. Let's read those results again, and notice that they give the raw measurements factored by the scaling distance and then state what that equals for each photo:

133A: gate bolt to screen = 30.4 mm. scaling dist. = 15.5 mm
30.4/15.5 = 1.96
133B: gate bolt to screen = 32.1 mm. scaling dist. = 15.2 mm
32.1/15.2 = 2.11 (6 HSCA 177-180)

The vertical parallax is 0.15 because the measured distances with the scaling distances factored in are 1.96 for 133-A and 2.11 for 133-B, and 2.11 minus 1.96 is 0.15. Vertical parallax is not a ratio: it is a measurement.

Not a blessed word about ratios in the PEP paragraph that introduces the calculations that determined the vertical parallax. They were talking about how they determined the vertical parallax. They factored in the scaling distance when calculating the measurements in order to determine the vertical parallax.

In order to determine the vertical parallax between corresponding points in two photos, you have to account for any differences in magnification. You do that just as the PEP: you pick other points and measure them horizontally.

If you answer nothing else, just answer two questions

1. Why do you suppose that the PEP said the vertical differences were "VERY SMALL" and that they showed that the camera moved only "SLIGHTLY downward" between the two exposures?

2. If the PEP were just introducing ratios, where is the vertical parallax stated? IOW, where is the vertical difference between the 133-A and the 133-B "MEASUREMENTS," if it's not in the calculations directly below the paragraph in question?

By what fiat have the Gods of Stupidity struck you senseless?! You quote the PEPs calculations that show that 1.96 and 2.11 are unitless ratios and not measurements or distances. In case you forgot, or maybe just have no idea what a ratio is, these are the ratio calculations that you've already quoted:

"133A: gate bolt to screen = 30.4 mm. scaling dist. = 15.5 mm
30.4/15.5 = 1.96

133B: gate bolt to screen = 32.1 mm. scaling dist. = 15.2 mm
32.1/15.2 = 2.11 (6 HSCA 177-180)"

30.4mm/15.5mm and 32.1mm/15.2mm are ratios. Period. The PEP uses the term "scale," which is a synonym of "ratio" in this context. I'm astounded you don't understand this. And, since the units cancel themselves out in the division, the results, 1.96 and 2.11, are unitless numbers and not distances. also, the difference of these two unitless numbers, 0.15, is also unitless. Period. You fail to grasp even basic mathematics. However, like any number of other fools, you try to compensate by ever-more sturm und drang to cover up the stench of your ignorance, and your stubborn foolishness to confront your own mistakes. The problem is, the rest of us see the whole sorry spectacle for what it is.

[Tom Graves]

By what fiat have the Gods of Stupidity struck you senseless?! You quote the PEPs calculations that show that 1.96 and 2.11 are unitless ratios and not measurements or distances. In case you forgot, or maybe just have no idea what a ratio is, these are the ratio calculations that you've already quoted:

"133A: gate bolt to screen = 30.4 mm. scaling dist. = 15.5 mm
30.4/15.5 = 1.96

133B: gate bolt to screen = 32.1 mm. scaling dist. = 15.2 mm
32.1/15.2 = 2.11 (6 HSCA 177-180)"

30.4mm/15.5mm and 32.1mm/15.2mm are ratios. Period. The PEP uses the term "scale," which is a synonym of "ratio" in this context. I'm astounded you don't understand this. And, since the units cancel themselves out in the division, the results, 1.96 and 2.11, are unitless numbers and not distances. also, the difference of these two unitless numbers, 0.15, is also unitless. Period. You fail to grasp even basic mathematics. However, like any number of other fools, you try to compensate by ever-more sturm und drang to cover up the stench of your ignorance, and your stubborn foolishness to confront your won mistakes. The problem is, the rest of us see the whole sorry spectacle for what it is.

Won mistakes, or own mistakes?

[Mitch Todd]

Won mistakes, or own mistakes?

own, but he definitely won some kind of prize for that performance.

[Lance Payette]

Since I have Michael on Eternal Ignore, I'm not quite following the debate, but paragraphs 442 and 444 of the PEP's report both explicitly refer to the measurements in question as "ratios." Ditto for paragraphs 432 and 433. If Michael is suggesting the difference between the ratios 1.96 and 2.11 is 15 mm, this is obviously ridiculous. How you actually compare two ratios is beyond my peewee mathematical abilities, but you don't subtract one from the other and declare the result in mm! All the measurements are showing is that the camera did in fact move - correct? More to the point, I find it difficult to believe the BYP are still being debated. Michael's threads remind me of visiting an oldies station and having to listen to Tommy James & The Shondells sing some dumbass song I hated when it first came out.

[Michael T. Griffith]

Since I have Michael on Eternal Ignore, I'm not quite following the debate, but paragraphs 442 and 444 of the PEP's report both explicitly refer to the measurements in question as "ratios." Ditto for paragraphs 432 and 433. If Michael is suggesting the difference between the ratios 1.96 and 2.11 is 15 mm, this is obviously ridiculous. How you actually compare two ratios is beyond my peewee mathematical abilities, but you don't subtract one from the other and declare the result in mm! All the measurements are showing is that the camera did in fact move - correct? More to the point, I find it difficult to believe the BYP are still being debated. Michael's threads remind me of visiting an oldies station and having to listen to Tommy James & The Shondells sing some dumbass song I hated when it first came out.

This whole discussion is unbelievable. Let's read those two paragraphs, shall we? "Ratios" refers to the scaling distances, which the PEP factored in to measure the horizontal and vertical parallax between 133-A and 133-B, and which was the basis of the panel's finding that there was horizontal and vertical camera movement between the two exposures. They factored in the scaling distances to account for the differences in magnification, as they explained in the paragraph that introduces the measurements that determined the vertical parallax.

Of course, when you're talking about scaling, yes, obviously, you're talking about ratio. But parallax is not a ratio. Parallax is the difference in the apparent position of objects viewed along two different lines of sight, in this case two different pictures of the same objects. You can Google it.

When dealing with photos, you apply the ratio of scaling to account for differences in magnification between the photos. Horizontal parallax is not a ratio. Vertical parallax is not a ratio. They are measurements of the distances between the same objects in two photos (or in two lines of sight). To determine the horizontal and vertical parallax in two photos, you factor in the scaling distance, i.e., you use the ratios of scale, to account for magnification variations in the photos, as the PEP explained in fairly plain English.

Before we read the two paragraphs you cite, let's keep in mind that the PEP said that their parallax measurements established that the camera moved only “slightly to the left” and only “slightly downward” between the two exposures, 133-A and 133-B, and that they found “very small” differences in the vertical distances between objects in the backgrounds of the photos (6 HSCA 178-179; 2 HSCA 416). Let's also remember that part of the cause of John Mytton's blunder was that he didn't realize the PEP took scale into account in their calculations.

Now, let's read the two paragraphs you cite:

(432) The panel determined that there had been horizontal camera movement. [How did the panel do this? Here's how]. It measured the difference in alinement between pictures of particular foreground and background objects. For example the prominent post in the foreground of each picture has a picket fence on both sides of it. The term "a" was designated as the distance from the left edge of the image of the post to the left edge of the left-hand picket at the end of the fence, "b" as the distance from the right edge of the image of the post to the right edge of the image of the right hand picket If the camera had moved between exposures the ratio of "b" to "a" should differ between viewpoints in different pictures

(433) This ratio was measured at three different heights on corresponding places on CE 133–A and B, and in all three instances a measurable difference was found. A similar technique was used with similar results to determine that there had also been vertical camera movement between pictures. (6 HSCA 175-176)

Did you catch that? By factoring in the ratio, i.e., the scaling distance (as they explain in paragraph 443), they found "a measurable difference," in horizontal positions, between the measured objects in the backgrounds. These statements, since are related to math, aren't quite as easy to understand as DiMaio's plain English statements about the behavior of FMJ bullets, but anyone with an adequate education should be able to grasp their meaning fairly easily.

Now let's read the PEP's paragraph that introduces the vertical parallax measurements:

(443) Vertical parallax was calculated by measuring the vertical distance from the center of the dark horizontal object, which looks like it might be a gate bolt or latch, to the bottom edge of the screen of the screen door in the background. (6 H 178-179)

Are we clear so far? What was calculated? "VERTICAL PARALLAX." Parallax is not a ratio. You may need to use ratios as part of your calculations to determine parallax, but parallax is a measurement of distance, not a ratio. You guys don't seem to understand what "parallax" means.

Let's continue as the PEP explains that the scaling distance, which of course involves ratio, was considered to take into account the differences in magnification, so that the "MEASUREMENTS" were related to the distance from the left edge of one picket to the left edge of the next:

To establish scale, that is to take into account differences in magnification, these measurements were related to the distance from the left edge of one picket to the left edge of the next, measured in a horizontal direction. This scaling distance was measured on the two center pickets of the four that appear to constitute the gate at the level of the lower edge of the top horizontal member. The results are as follows: (6 HSCA 178-179)

"The RESULTS." The "RESULTS" for what? For "VERTICAL PARALLAX." What does the term "results" mean when used in math? Here's what it means: "The final answer to a calculation and a proven mathematical statement." You can Google this too, if you don't believe me.

The very first sentence in the paragraph on vertical parallax, paragraph 443, tells us that we're being told how the PEP calculated the "VERTICAL PARALLAX." And in the process of calculating the "VERTICAL PARALLAX," what did they do to account for the differences in magnification? They established the scaling distance for each photo, which was different for each photo.

And then, in the last sentence of the paragraph, the PEP said, "The results are as follows." And here are the "the RESULTS" for the "VERTICAL PARALLAX":

133A: gate bolt to screen = 30.4 mm. scaling dist. = 15.5 mm
30.4/15.5 = 1.96
133B: gate bolt to screen = 32.1 mm. scaling dist. = 15.2 mm
32.1/15.2 = 2.11 (6 HSCA 177-180)

And what are "results" again when used in math? Let's read what Google AI says:

Numerical answer: The most common use is the number or value obtained after performing a mathematical operation or solving a problem.

Example: In the expression 3 x 6 + 1, the result is 19.

Synonyms: In this context, "result" is often used interchangeably with "answer" or "solution".

If those "results" are not the vertical parallax between the two photos, even though the PEP plainly said they are, where did the PEP state the vertical parallax, pray tell? Did they just forget to state it? Where is it?

And, leaving aside your refusal to acknowledge the plain meaning of the PEP's statements about the parallax measurements, are you guys ever going to address the fact that the PEP said those measurements proved that the camera moved only "SLIGHTLY" horizontally and vertically between exposures, and that the differences in the vertical parallax in the photos is "VERY SMALL"?

How in the world do you get only slight horizontal and vertical camera movement in photos taken in the manner in which the backyard rifle photos were allegedly taken? Such a feat would be difficult for a professional photographer using a modern camera to achieve. It would be impossible to achieve using a cheap handheld camera with a lever that had to be manually pushed downward to take the picture and with the camera being handed back and forth twice so the film could be forwarded.

[Mitch Todd]

This whole discussion is unbelievable. Let's read those two paragraphs, shall we? "Ratios" refers to the scaling distances, which the PEP factored in to measure the horizontal and vertical parallax between 133-A and 133-B, and which was the basis of the panel's finding that there was horizontal and vertical camera movement between the two exposures. They factored in the scaling distances to account for the differences in magnification, as they explained in the paragraph that introduces the measurements that determined the vertical parallax.

Of course, when you're talking about scaling, yes, obviously, you're talking about ratio. But parallax is not a ratio. Parallax is the difference in the apparent position of objects viewed along two different lines of sight, in this case two different pictures of the same objects. You can Google it.

When dealing with photos, you apply the ratio of scaling to account for differences in magnification between the photos. Horizontal parallax is not a ratio. Vertical parallax is not a ratio. They are measurements of the distances between the same objects in two photos (or in two lines of sight). To determine the horizontal and vertical parallax in two photos, you factor in the scaling distance, i.e., you use the ratios of scale, to account for magnification variations in the photos, as the PEP explained in fairly plain English.

Before we read the two paragraphs you cite, let's keep in mind that the PEP said that their parallax measurements established that the camera moved only “slightly to the left” and only “slightly downward” between the two exposures, 133-A and 133-B, and that they found “very small” differences in the vertical distances between objects in the backgrounds of the photos (6 HSCA 178-179; 2 HSCA 416). Let's also remember that part of the cause of John Mytton's blunder was that he didn't realize the PEP took scale into account in their calculations.

Now, let's read the two paragraphs you cite:

(432) The panel determined that there had been horizontal camera movement. [How did the panel do this? Here's how]. It measured the difference in alinement between pictures of particular foreground and background objects. For example the prominent post in the foreground of each picture has a picket fence on both sides of it. The term "a" was designated as the distance from the left edge of the image of the post to the left edge of the left-hand picket at the end of the fence, "b" as the distance from the right edge of the image of the post to the right edge of the image of the right hand picket If the camera had moved between exposures the ratio of "b" to "a" should differ between viewpoints in different pictures

(433) This ratio was measured at three different heights on corresponding places on CE 133–A and B, and in all three instances a measurable difference was found. A similar technique was used with similar results to determine that there had also been vertical camera movement between pictures. (6 HSCA 175-176)

Did you catch that? By factoring in the ratio, i.e., the scaling distance (as they explain in paragraph 443), they found "a measurable difference," in horizontal positions, between the measured objects in the backgrounds. These statements, since are related to math, aren't quite as easy to understand as DiMaio's plain English statements about the behavior of FMJ bullets, but anyone with an adequate education should be able to grasp their meaning fairly easily.

Now let's read the PEP's paragraph that introduces the vertical parallax measurements:

(443) Vertical parallax was calculated by measuring the vertical distance from the center of the dark horizontal object, which looks like it might be a gate bolt or latch, to the bottom edge of the screen of the screen door in the background. (6 H 178-179)

Are we clear so far? What was calculated? "VERTICAL PARALLAX." Parallax is not a ratio. You may need to use ratios as part of your calculations to determine parallax, but parallax is a measurement of distance, not a ratio. You guys don't seem to understand what "parallax" means.

Let's continue as the PEP explains that the scaling distance, which of course involves ratio, was considered to take into account the differences in magnification, so that the "MEASUREMENTS" were related to the distance from the left edge of one picket to the left edge of the next:

To establish scale, that is to take into account differences in magnification, these measurements were related to the distance from the left edge of one picket to the left edge of the next, measured in a horizontal direction. This scaling distance was measured on the two center pickets of the four that appear to constitute the gate at the level of the lower edge of the top horizontal member. The results are as follows: (6 HSCA 178-179)

"The RESULTS." The "RESULTS" for what? For "VERTICAL PARALLAX." What does the term "results" mean when used in math? Here's what it means: "The final answer to a calculation and a proven mathematical statement." You can Google this too, if you don't believe me.

The very first sentence in the paragraph on vertical parallax, paragraph 443, tells us that we're being told how the PEP calculated the "VERTICAL PARALLAX." And in the process of calculating the "VERTICAL PARALLAX," what did they do to account for the differences in magnification? They established the scaling distance for each photo, which was different for each photo.

And then, in the last sentence of the paragraph, the PEP said, "The results are as follows." And here are the "the RESULTS" for the "VERTICAL PARALLAX":

133A: gate bolt to screen = 30.4 mm. scaling dist. = 15.5 mm
30.4/15.5 = 1.96
133B: gate bolt to screen = 32.1 mm. scaling dist. = 15.2 mm
32.1/15.2 = 2.11 (6 HSCA 177-180)

And what are "results" again when used in math? Let's read what Google AI says:

Numerical answer: The most common use is the number or value obtained after performing a mathematical operation or solving a problem.

Example: In the expression 3 x 6 + 1, the result is 19.

Synonyms: In this context, "result" is often used interchangeably with "answer" or "solution".

If those "results" are not the vertical parallax between the two photos, even though the PEP plainly said they are, where did the PEP state the vertical parallax, pray tell? Did they just forget to state it? Where is it?

And, leaving aside your refusal to acknowledge the plain meaning of the PEP's statements about the parallax measurements, are you guys ever going to address the fact that the PEP said those measurements proved that the camera moved only "SLIGHTLY" horizontally and vertically between exposures, and that the differences in the vertical parallax in the photos is "VERY SMALL"?

How in the world do you get only slight horizontal and vertical camera movement in photos taken in the manner in which the backyard rifle photos were allegedly taken? Such a feat would be difficult for a professional photographer using a modern camera to achieve. It would be impossible to achieve using a cheap handheld camera with a lever that had to be manually pushed downward to take the picture and with the camera being handed back and forth twice so the film could be forwarded.

1.) The PEP brought up the parallax issue in response to the allegations "that the backgrounds in these pictures are identical and that three differently posed subjects had been superimposed on copies of one background picture." But any difference in parallax completely destroys any notion that the backgrounds are identical, even if the difference is "very small."

2.) The point I made, which is the subject of this particular subthread, is that the PEP calculated values 1.96 and 2.11 are neither measurements nor calculated distances, but unitless ratios. This should be trivially obvious on even cursory examination of the mathematical expressions by which they were calculated.

I look forward to seeing how many more words you are willing to send into horrific mass slaughter this time, all in order to defend what is simply indefensible. I will mourn their pointless deaths in the face of vain futility, but I will savor the schadenfreude nonetheless.

[Michael T. Griffith]

1.) The PEP brought up the parallax issue in response to the allegations "that the backgrounds in these pictures are identical and that three differently posed subjects had been superimposed on copies of one background picture." But any difference in parallax completely destroys any notion that the backgrounds are identical, even if the difference is "very small."

One, you still don't seem to understand what "parallax" means. "Any difference in parallax"? What you should have said is "Any parallax." The term "parallax" means a difference in an object's position when viewed from two different perspectives. If you don't believe me, maybe you'll believe Google AI:

Vertical parallax is the vertical separation between two homologous points in a stereopair of images. In optical and surveying contexts, vertical parallax must typically be eliminated to achieve a clear, stereoscopic view because it can cause eye strain and inaccurate depth perception. 

Or maybe you'll believe the University of Kansas:

Horizontal parallax describes the horizontal separation between two homologous points. . . .

Vertical parallax describes the vertical separation between two homologous points. (https://people.eecs.ku.edu/~jrmiller/Stereo/Section_05/Page_0020.php)

Two, the tiny parallax that the PEP detected does not prove the backgrounds are not the same. Simply slightly key-stoning the same background for three pictures could create the very small parallax that the PEP detected, which the PEP could only detect with computer-aided measurements and with high-magnification analysis, because the differences in distances between the background objects are too small to discern with the naked eye.

2.) The point I made, which is the subject of this particular subthread, is that the PEP calculated values 1.96 and 2.11 are neither measurements nor calculated distances, but unitless ratios. This should be trivially obvious on even cursory examination of the mathematical expressions by which they were calculated.

Okay, then where are the measurements that specify the vertical parallax? The paragraph that introduces the numbers in question says the measurements were done to calculate vertical parallax:

Vertical parallax was calculated by measuring the vertical distance from the center of the dark horizontal object to the bottom edge of the screen of the screen door in the background. . . . The results are as follows: (6 HSCA 178-179)

I trust you know what the term "results" means when used in a math context, right? Right? Yes?

So, again, where are "the results" of the "measuring" when "vertical parallax was calculated"? What was the vertical parallax? What was the difference in cm or mm between the measured vertical distances? Where is this crucial information?

Give me the paragraph and page number in the PEP report. This should be really easy, unless you're going to argue that the PEP inexplicably "forgot" to provide the vertical parallax, i.e., the difference between the 133-A and 133-B vertical measurements, or, even worse, that they withheld this crucial datum. When you go looking for the vertical parallax, keep in mind that, by definition, parallax in photos is the difference in distances between background objects when viewed from two different perspectives.

I look forward to seeing how many more words you are willing to send into horrific mass slaughter this time, all in order to defend what is simply indefensible. I will mourn their pointless deaths in the face of vain futility, but I will savor the schadenfreude nonetheless.

And I look forward to seeing you tell all of us where the vertical parallax is given in the report, if it is not included in "the results" that the PEP said came when "vertical parallax was calculated."

Here's a golden opportunity for you to quit your usual ducking and dodging and your usual act of refusing to acknowledge the meaning of key terms--you know, like "measuring," "measurements," "parallax," and "results." Here's your chance to blow me out of the water.

All you gotta do is tell me where the vertical parallax is given in the PEP report. You know, like "the difference between the 133-A and 133-B vertical measurements is X mm/cm." Or, just like "the 133-A vertical distance between the measured points is X mm/cm, and the 133-B vertical distance between the measured points is X mm/cm," so we can easily determine the vertical parallax.

And while you're at it, it would be extra nice if you would explain how photos taken with a cheap top-view camera with a lever for a button and with the camera allegedly handed back and forth twice so Oswald could forward the film--how those photos could contain such tiny differences in the distances between the background objects and could indicate only "slight" horizontal and vertical camera movement between exposures.

For the sake of any newcomers and guests, we're talking about the fact that the PEP attempted to explain the apparent sameness of the backgrounds by announcing that their photogrammetric measurements found that the camera moved “slightly to the left” and “slightly downward” between exposures, and that the camera’s vertical movement was “very small” (6 HSCA 178-179; 2 HSCA 416).

In doing this, the PEP inadvertently provided strong evidence of forgery in the photos, because the camera’s horizontal and vertical movement would have been much greater if the photos had been taken in the manner claimed by the official story. If these photos had been taken by twice handing the camera back and forth and with a camera that had a lever that had to be physically pushed down to take a photo, the differences in the distances between objects in the backgrounds would be much larger, would not be invisible to the naked eye, and would not be undetectable without computer-aided photogrammetric measurements and the use of microscopes.

The PEP had to use computer-aided photogrammetric measurements and microscopes/high magnification to detect the camera’s slight horizontal and vertical movement and the tiny differences in horizontal and vertical distances between objects in the backgrounds of the photos 133-A and 133-B.

In doing the photogrammetric measurements to detect parallax, the PEP performed “computer-assisted photographic evaluation” and also performed “examination under magnification with magnifiers and microscopes” (2 HSCA 398, 405).

Why? Because the tiny differences in the distances between background objects are invisible to the naked eye and can only be discerned with computer-aided and microscope-aided photogrammetric measurements.