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infocusinc
2002-Apr-18, 03:05 AM
<font size=-1>[ This Message was edited by: infocusinc on 2002-04-18 15:16 ]</font>

JayUtah
2002-Apr-18, 02:29 PM
I grabbed the photos from the JFK Research uploads directory. Of course I don't have the benefit of the supporting discussion, but is White actually claiming that the crosshairs should align with the objects in the image and not with the frame?

Is he also claiming that rotating the camera about the optical axis will produce a different affine projection? If so, then:

1. How can someone billing himself as a top-notch photo analyst be so mystified by a reseau grid, how it's made, and what it's used for?

2. How can someone billing himself as a top-noth photo analyst be so utterly ignorant of the geometry of light as it goes through a camera?

3. (My perennial question) Why does anyone listen to Jack White?

johnwitts
2002-Apr-18, 08:05 PM
Talking to yourself, Jay? What did Infocusinc write?

I've read through the posts at JFK and they are real tripe. Jack White cannot see even the simplest error in his analysis, so a whopper would be right over his head.

JayUtah
2002-Apr-18, 08:35 PM
Infocusinc was talking about a discussion at JFK. All I get are the example photos, not the discussion, so it's like watching a newscast with the volume turned down. Apparently White believes that rotating a camera around the optical axis without displacing it should produce a difference in the appearance of objects in the photo.

johnwitts
2002-Apr-18, 08:55 PM
I wouldn't worry about it. Craig has him good this time. Jack is trying to use photometry on tiny portions of larger photos (what's new?). As a consequence, if Jack posted a photo of me with the simple caption 'This is John', I'd have a hard time believing him.

infocusinc
2002-Apr-19, 04:14 AM
Ive been asked not to post on the moon issue at JFK if I want to keep posting rights. Guess they got a little mad at me.

Anyway, the debate NOW (its ever shifting at JKF) concerns AS12-46-6726 and 6727.

White claimed that when you compare 26 to 27, 27 has camera rotation to the left and the camrea was ained a bit more to the right. He claims (now with the support of John Costella that three is less that 1/2" of movement of the lens in relation to the LM, rotation or tilt aside. The claim is that this just might not be possible froma cameraman using eithe a hand held or chest mounted camera. Costella says its seems strange and White claims it could omly be done with a tripod. Costella who said he does not even know how bg the lm is, has calculated the lens movement to less than 1/2 inch.

Thats the current question.

Craig

JayUtah
2002-Apr-19, 05:59 AM
Well, I'll quibble with their measurements. Jack White has zero credibility, and the other guy has made incorrect simplistic arguments in the past. If they don't even know how big the LM is, I can't imagine the basis of their computation is very sound.

Further, if you examine the various EVA videos you'll find that the astronauts don't move around a whole lot while "planted" in one spot. Since the camera was affixed to the RCU via a sort of bayonet fixture, it won't move much relative to the astronaut. Consider Conrad pulling the trigger with his right hand and winding frames with his left. I don't see why there must necessarily be more movement. The question is not whether two photos were taken from basically the same position, but whether all the photos were taken from the same point. If two out of six or eight match, that's a coincidence. If all six or eight match, then you can start talking about tripods.

Donnie B.
2002-Apr-19, 11:35 PM
On 2002-04-18 16:35, JayUtah wrote:
Apparently White believes that rotating a camera around the optical axis without displacing it should produce a difference in the appearance of objects in the photo.

Well, I believe it too. All objects appear to be rotated by X degrees... /phpBB/images/smiles/icon_biggrin.gif

JayUtah
2002-Apr-19, 11:45 PM
Yeah, I couldn't figure out how to word that. /phpBB/images/smiles/icon_smile.gif It looks like White is arguing that if you crop two photos that share an optical axis and eyepoint, so that they are identically framed, you should be able to tell which photo was originally taken at what angle.

There's only one obscure condition under which that would be true: if the lens provides a very nonlinear affine projection across the field of view, and the objects in question lie near the image boundaries. The Zeiss Biogon was specifically engineered to provide as linear a projection as possible, so that's not really a factor here, and the objects in question lie near the optical axis where any such effect would be negligible.

Anyhow I don't think this is what White is talking about.

Donnie B.
2002-Apr-19, 11:53 PM
Right, something like a Panavision lens would do that.

In any case, with the reticules, it would be very easy to convince yourself you were seeing distortions, when you were really being tricked by the difference in crosshair angles. That's a very common optical illusion.

JayUtah
2002-Apr-20, 01:58 AM
No, I'm not talking about anamorphic lenses. It's a feature of any lens.

In any case I just did the math and the feature I'm talking about would, in fact, be invariant given only an axial rotation. Sorry, Jack. That was the last leg he could have stood upon.

infocusinc
2002-Apr-20, 02:44 AM
Guys the big thing here is the fact that the camera was not rotated around the optical axis. In addition to film plane rotation there is a change in the "tilt" of the film plane happening also. That causes perspective changes between the two images in question. In a12-46-6727 the camera has not only been rotated about 4 degrees but it appears to have been turned to the right about 4 degrees away from the lm. I have to speculate that Conrad did this because a very bright reflection from the sun was bouncing off the side of the lm. It is seen in most of the photos in this series. While he had no viewfinder to see if this glare was in his framing, it had to be hitting him in the eyes the same way. In fact he makes a bunch of comments about the sun and not being able to see when they are raising and lowering the equipment bag. Thats why he turned and the camera went with him. In the process this rotation and tilt took place. By itself the rotation should produce do changes in the spacial relationships of the objects in the photograph. The tilting did. In 6727 the LM grows larger on picture left and smaller on picture right. The perspective has changed. So it makes comparing the images hard.

So how does all of that mesh with the tripod claim. We are working from a premise that within every photograph lies an infinite number of indivdual lines of sight extending radially from the camera. Each of these lines of sight is made of three points, the camera, and point in the scene some distance from the camera, and another point in the scene even farther away from the camera. These three point comprise a line. And this line works like a lever, and pivots on the middle point. As you move the camera either right or left or up and down the point that represents the camera also moves. When this point moves the point at the other end will move in the opposite direction ... a little lever action. The point of all of this is that you can measure and calculate all of this and figure out now much the camera has moved, or where the camera was. Jack has decided that when comparing 6726 and 6727 that there has been no deviation in the actual lens position between frames (including the film plane rotation and tilt) and that is impossible to do without a tripod.

Sorry to get so windy. I know this started out as a crosshair post, and that is where Jack started as well, but dropped that one...now its tripods...go figure!

Craig

JayUtah
2002-Apr-20, 05:47 AM
In addition to film plane rotation there is a change in the "tilt" of the film plane happening also. That causes perspective changes between the two images in question.

In theory it shouldn't. But it brings any nonlinearity of the lens back into the question, although in a very minor -- probably negligible -- role in this case.

Rotations in any axis around the focal point do not change the theoretical affine projection. This includes rotations that change the surface normal of the film plane. You could rotate the camera ad nauseam around its focal point without altering any lines of sight.

Now in practice most camera rotations do not occur around the focal point. They occur around a point significantly to the rear of the focal point. This is especially true of an RCU-mounted Apollo camera. If the astronaut turns to reorient the camera, he has displaced the focal point, and this will set up a new affine space.

Each of these lines of sight is made of three points, the camera, and point in the scene some distance from the camera, and another point in the scene even farther away from the camera.

To be more specific, the first point is the focal point. Otherwise I agree with this.

Jack has decided that when comparing 6726 and 6727 that there has been no deviation in the actual lens position between frames (including the film plane rotation and tilt) and that is impossible to do without a tripod.

Okay, this makes a lot more sense than the argument I gleaned from the photographs discussing rotation measured by fiducials.

Unfortunately it's impossible with a tripod too. A tripod does not (and in fact cannot) rotate a camera about its focal point. The focal point actually lies inside the lens. The axes of a tripod head usually lie behind and significantly below this point. Therefore any "pan" or "tilt" of the camera will displace the focal point and alter the affine space of the image.

If White wishes to argue that it's too coincidental for the focal point to be in the same place twice while the camera is mounted on an astronaut's RCU, then for my money he'll have to explain how it coincidentally happened that way on a tripod. Besides, I don't think White and his associates have a good track record of measuring lines of sight in photographs.

Johnno
2002-Apr-20, 08:09 AM
Speaking of Jack White, he's now going through the 'visor reflections' and 'trackless rover' claims.

Reckon Ill just sit tight til there's something that I just cant let pass...

David Hall
2002-Apr-20, 10:05 AM
What's the point about a tripod anyway?
If I were trying to create a believable hoax, I would as much as possible make it true to life. In other words, I'd have everyone 'go through the motions' as if it were the real thing. The very idea of using a tripod or other unneccesary prop just increases the risk of something going wrong.

But then again, I'm sure the HB's would just come up with one or another reason why the tripod had to be there. You can't win. :rolleyes:

infocusinc
2002-Apr-20, 12:42 PM
[quote]
On 2002-04-20 06:05, David Hall wrote:
What's the point about a tripod anyway?


Exactly. Its a stupid argument. Jay is correct when he states it cant be done witha tripod either, they just dont work that way.

And Jack is trying to find camera movement from two points on the lm that are really close together. If we take our three points that form our line of sight, with the focal point being say 15 feet from the lm and the two remaining points being only inches apart on the lm, the lever action dictates that the camera must be moved a great deal to see any movement of the third point in the line.

JayUtah
2002-Apr-20, 01:53 PM
Jay is correct when he states it cant be done witha tripod either, they just dont work that way.

The human head doesn't even work that way. The focal point for your eyeballs is just behind the lens, somewhere in the jelly goo between it and the retina. The pivot point is somewhere along your neck.

Place a candle or other thin object on a window sill. Stand a comfortable distance from the window so you can see the candle against the background of a distant object. Now close one eye and turn your head slowly left and right while tracking the candle by moving your eyeball. You should notice a subtle change in how the candle obscures parts of the background, as well as an increase in attention to your behavior from other people in the room.

The candle appears to move relative to the background because even though you're keeping your body still, the eyeball's focal point is moving as well as changing direction. The change in direction is not what causes the apparent movement of the candle, but the change in location of the focal point because your eyes are located so far from the pivot point of your head.

JayUtah
2002-Apr-20, 02:04 PM
The very idea of using a tripod or other unneccesary prop just increases the risk of something going wrong.

And the risk of "foreign" photographic equipment being seen in reflections and shadows.

Anybody remember Logan's Run, the 1970-something film? There's a fanciful character whose costume consists of many planar reflective surfaces. Freeze-frame it as he turns and you can clearly pick out equipment and members of the crew. Compare this with Vertical Limit where the actors all wear mirrored sunglasses. The filmmakers in this case put tarps over the camera, or used other methods to hide it in the reflection. So in that case it doesn't jump out at you and say, "I'm a camera." But to some of us it looks like a camera covered by a tarp -- just as foreign.

One of the major shortcomings of the conspiracy theories is the total lack of any direct proof for the equipment and methods they say were used to produce the forgeries. Most of us can find such goofs in feature films. They're inevitable.

Hoax believers don't try to establish a belief based on evidence, they try to compel a belief. There's a difference. In this case, White makes an observation. He claims the observation could only be the result of a particular process. Ergo the process must have existed. He cannot provide any direct evidence for a tripod, only an effect that he says can only be produced by a tripod. So even though the use of a tripod for this photo implies a very improbable thing, he compels you to believe it must have been so since "no other possibility exists."

Occasionally hoax believers point to lots of little visor spots or ghostly things in backgrounds and say, "See, that's the equipment." Unfortunately the equipment they say they see isn't the appropriate equipment for producing the effects they say they see. For example, it's pretty common to point out a "row of lights" in the visor reflection, when in fact such a row of lights would completely ruin the shadow that's being cast.

Ian R
2002-Apr-20, 11:34 PM
<center>http://www.hq.nasa.gov/alsj/a12/20128948.jpg</center>



AS12-46-6724



Although the quality of this image is very poor, it is good enough to show the light reflecting off of the insulation on the LM's descent stage. This is the source of light that produces the effects seen in the later egress pictures.

Ian R
2002-May-10, 03:40 AM
<font size=-1>[ This Message was edited by: Ian R on 2002-05-10 14:25 ]</font>