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Post by HeadLikeARock (was postbaguk) on Jan 31, 2007 21:03:11 GMT -4
For some reason I can't post a comment on Youtube, so I'll bung it in here in case someone else wants to use it. Taken with a Fuji F10, no zoom. No cropping. Colour removed. Contrast enhanced in photoshop. No other alterations. Oh, apart from the arrows I added.
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Post by Joe Durnavich on Jan 31, 2007 21:32:30 GMT -4
That's the way to do it: Simply go outside and see for yourself. Here is a shadow vanishing point analysis I did that shows how to verify consistency of shadow directions. The direction of the shadow on the ground is generally not relevant. The key is match points on objects to points in their shadows. This marks the path of rays of sunlight that just graze the edges of objects: home.earthlink.net/~joejd/images/as14vpa.jpgWhen the sun is at the photographer's back, the VPA works out like so: home.earthlink.net/~joejd/images/moon1vpa.jpgAnd this one I did on one of Jack White's graphics. White drew the blue arrows to mark what he thought the shadow directions are. I drew the red lines to mark the actual direction of sunlight, and thus, the actual direction of shadows: home.earthlink.net/~joejd/images/vpajw1.jpg
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Post by Apollo Gnomon on Jan 31, 2007 21:37:55 GMT -4
If by "no zoom" you mean zoomed all the way out, then you are using a "wide angle" lens setting. From a random review of the Fuji f10 camera: • Fujinon 36 - 108 mm equiv. (3x optical zoom)The Lunar Hasselblad cameras used a wide angle lens "This lens would have a maximum aperture of f/5.6 and a focal length of 60 mm." www.mir.com.my/rb/photography/hardwares/moon/2.htmI don't remember what a "normal" lens for the Hasselblad film is, but 80mm comes to mind. Normal lens for a 35mm camera is 50mm. This is exactly what I've been saying - the shadows show the effects of a wide angle lens. The shadows point more toward the center of frame, not actually horizontally, in your case.
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Post by Joe Durnavich on Jan 31, 2007 21:50:43 GMT -4
I don't remember what a "normal" lens for the Hasselblad film is, but 80mm comes to mind. Normal lens for a 35mm camera is 50mm.
One rule-of-thumb I have seen is that a normal lens is roughly the same size as the diameter of the film image. The Hasselblad image is 55 mm x 55 mm, or 78 mm diagonally. 80 mm, then, would be normal and 60 mm wide-angle, or perhaps, medium-wide.
This is exactly what I've been saying - the shadows show the effects of a wide angle lens.
We might want to be careful how we word this (in case an HB throws it back at us). The lens doesn't cause the effect. You can see the effect with your own eyes. You notice the variant shadow directions more in wide-angle photographs because they capture more of the scene.
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Post by HeadLikeARock (was postbaguk) on Jan 31, 2007 22:17:26 GMT -4
If by "no zoom" you mean zoomed all the way out, then you are using a "wide angle" lens setting. From a random review of the Fuji f10 camera: • Fujinon 36 - 108 mm equiv. (3x optical zoom)The Lunar Hasselblad cameras used a wide angle lens "This lens would have a maximum aperture of f/5.6 and a focal length of 60 mm." www.mir.com.my/rb/photography/hardwares/moon/2.htmI don't remember what a "normal" lens for the Hasselblad film is, but 80mm comes to mind. Normal lens for a 35mm camera is 50mm. This is exactly what I've been saying - the shadows show the effects of a wide angle lens. The shadows point more toward the center of frame, not actually horizontally, in your case. I'm willing to take your word on the details. The point is, it's quite easy to recreate a similar effect to that shown in the video that Jarrah White claims is proof of fakery. If I had a "proper" camera with a wide-angle lens, I suspect the effect would be more marked. If I had an equivalent Hasselblad, I'd be able to recreate the effect almost exactly.
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Post by PhantomWolf on Feb 1, 2007 0:48:58 GMT -4
The effect is from two sources. One is parallax, like you get with train tracks heading into the distance. The other is distance shortening. The shadow looks shorter because you see it at a smaller angle, that throws off the dimentions and our brain readjusts what it is seeing. Since we expect the shadow to be longer then wide, it interprets the longer part of the shadow as the length when it actually isn't. I think in many ways this is actually the greater affect in the image, though the parallax can be quite dramatic as well as you can see in some of the Apollo 12 images where the shadows of the Antenna and flag appear
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Post by HeadLikeARock (was postbaguk) on Feb 1, 2007 4:58:46 GMT -4
Perhaps I should mention I'm well aware that the rock shadows weren't actually running in the direction indicated - I was trying to compare the photo with how an HBer would interpret the image.
With hindsight, I should have taken some photos of the rock shadows from the side, to show how long they actually were.
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Post by Mr Gorsky on Feb 1, 2007 5:02:37 GMT -4
Got to love that lovely fuzzy edge to the shadow of the photographer too!
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Post by HeadLikeARock (was postbaguk) on Feb 1, 2007 7:06:34 GMT -4
Got to love that lovely fuzzy edge to the shadow of the photographer too! Nah, that's just me - fuzzy edged!
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Post by Joe Durnavich on Feb 1, 2007 9:09:17 GMT -4
With hindsight, I should have taken some photos of the rock shadows from the side, to show how long they actually were.
I was thinking about Phantom Wolf's explanations and appreciating just how non-intuitive perspective effects can be.
Notice how the shadow of the right rock in your photo "points to the left." If there was a second photo taken at the same time as the first one from a position to the right of this rock so that is was on the left of the frame, then the shadow would "point to the right." I bet it would blow the conspiracy theorists minds that with the sun as the sole light source, the same rock casts a single shadow that is somehow both to the left and to the right of the same rock at the same time.
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Post by HeadLikeARock (was postbaguk) on Feb 1, 2007 12:33:45 GMT -4
With hindsight, I should have taken some photos of the rock shadows from the side, to show how long they actually were.I was thinking about Phantom Wolf's explanations and appreciating just how non-intuitive perspective effects can be. Notice how the shadow of the right rock in your photo "points to the left." If there was a second photo taken at the same time as the first one from a position to the right of this rock so that is was on the left of the frame, then the shadow would "point to the right." I bet it would blow the conspiracy theorists minds that with the sun as the sole light source, the same rock casts a single shadow that is somehow both to the left and to the right of the same rock at the same time. I feel another trip to the beach coming on!
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Post by gwen on Feb 1, 2007 13:09:02 GMT -4
Phanton Wolf's illustrations are a very helpful way to see how any photograph is a record of light bouncing back in 3D onto a flat (2D) plane. As he said, our eyes work rather much the same way (with the help of wee 3D parallax shift hints cuz most of us have 2 of 'em) but our brains automatically interpret all this stuff, along with the warped look of converging shadows, with no conscious effort from ourselves so they don't strike us as at all odd. Meanwhile I don't think even half the people who come up with these hoax interpretations believe them, I think they're targeted at the gullible, for the purpose of selling books and videos.
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Post by BertL on Feb 1, 2007 13:47:22 GMT -4
Welcome, gwen.
Well, this will probably provide enough information for jolly old Jarrah White to chew on. Jarrah, in case you're reading this: I knew you'd read this!
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Post by gwen on Feb 1, 2007 13:54:59 GMT -4
Welcome, gwen. Well, this will probably provide enough information for jolly old Jarrah White to chew on. Jarrah, in case you're reading this: I knew you'd read this! Haha! I glark he knows what he's up to. ;D
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Post by Joe Durnavich on Feb 1, 2007 20:00:28 GMT -4
Phanton Wolf's illustrations are a very helpful way to see how any photograph is a record of light bouncing back in 3D onto a flat (2D) plane.
Of all the light rays bouncing around out there in the environment, you detect only those that converge on your eyes. Detecting only the converging rays means that your field of view expands with distance from you. Railroad tracks appear to converge in the distance because your field of view expands faster with distance from you, so to speak, then the distance between the two tracks, which is constant. So, it is not really the 2D retina that cause the perspective effect as it is the fact that you are so selective of the light rays that you sample from the environment.
As he said, our eyes work rather much the same way (with the help of wee 3D parallax shift hints cuz most of us have 2 of 'em) but our brains automatically interpret all this stuff, along with the warped look of converging shadows, with no conscious effort from ourselves so they don't strike us as at all odd.
The way I that have been thinking about it is, the odd, by definition, is that which is unusual or puzzling. You spend your whole life viewing the world in perspective. You take converging tracks and the like as normal.
I think the odd comes in when the conspiracy theorist draws the arrows on the photo and then challenges you to explain them. This forces you to think about a matter that you probably hardly ever notice or worry about. Being at a loss to explain the shadows is where the feeling of oddness arises.
Part of the problem, as we have been noting here, is that the arrows they draw often have little to do with the true shadow direction. The shadow on the ground is simply where the shadow volume intersects the ground. The conspiracy theorist wants you to think that is the direction the light travels.
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