It looks like you're using an Ad Blocker.

Please white-list or disable AboveTopSecret.com in your ad-blocking tool.

Thank you.

 

Some features of ATS will be disabled while you continue to use an ad-blocker.

 

New Analysis Video of the STS-75 Tether Incident

page: 100
77
<< 97  98  99    101  102  103 >>

log in

join
share:

posted on Nov, 28 2009 @ 01:57 PM
link   
reply to post by poet1b
 


I don't understand it, are you saying that what we see on the tether video is a result of spherical aberration and not because they are out of focus?

Or are you saying that it's both things, that they (or at least some of them) look that way because they are out of focus and because of spherical aberration?

PS: I think that page was posted some months back in this thread (or in another thread about this video), but I am not sure.




posted on Nov, 28 2009 @ 04:01 PM
link   
reply to post by ArMaP
 


I am saying it works the way it is described in the links I have provided, taking all the variables into consideration. Focus is the point of concentration determined by the distance from the lens to the sensing device or film. In video the other considerations are aperture and film speed.



posted on Nov, 28 2009 @ 04:07 PM
link   
reply to post by poet1b
 





In video the other considerations are aperture and film speed.

Film speed? That's twice you've mentioned film speed. This is a film camera? When did we find that out? I thought this was a video camera. There is no "film speed" in a video camera. There isn't any film in a video camera. Do you know what "film speed" means?

A statement like this makes one wonder if you understand anything of what you are talking about.


[edit on 11/28/2009 by Phage]



posted on Nov, 28 2009 @ 04:47 PM
link   

Originally posted by poet1b
reply to post by ArMaP
 

In video the other considerations are aperture and film speed.


You're misusing either the term "video" or "film speed". The latter refers to non-electronic recordings using film, the former refers to electronic recordings using electronic recording methods in place of film.

reply to post by poet1b
 


Yes photography has been a hobby of mine for many years.

You are mistaken in thinking spherical aberration could be a source for the donut shaped bokeh, the bokeh is an issue of focus/aperture.

Let me present a thought experiment to see if it helps. If the tether was say 3 or 4 meters away, then I think it would be possible to have bokeh either in front of, or behind the tether, consistent with the depth of field tables.

But given that the closest approach to the tether was tens of kilometers away, there is virtually no way the bokeh could be behind the tether at any aperture (depth of field) setting, unless the tether was at least as out of focus as the bokeh, and it's not that much out of focus.

I'm impressed to see you doing research since you don't have photography as a hobby, and thanks for sharing your research sites with us but a lot of us photographic hobbyists already know that stuff. It seems like some of what you're reading isn't registering, and I suspect that's because reading about something is really no substitute for field work with hands-on experience, that might make the difference where everything would click for you, or in lieu of that, you could try asking someone who DOES have the hands on experience.

[edit on 28-11-2009 by Arbitrageur]



posted on Nov, 28 2009 @ 04:50 PM
link   
reply to post by Phage
 


You really don't have a clue.

What year was this video shot?

What year do you think the cameras used to shoot this video were Space Flight Certified?

It is very probable that this was recorded originally on film, and I think we have already established that the original signal was sent in analog, not digital, so it was not shot in digital.

Before you go insulting people, you should probably know what you are talking about, or else you look like an idiot as well as a jerk.



posted on Nov, 28 2009 @ 04:56 PM
link   
reply to post by poet1b
 


Well since STS-75 was in 1996, I suppose the video was shot in 1996.

This document:
www.shuttlepresskit.com...
tells us that this video was made with a closed circuit television camera (yes, analog). Part of the whole CCTV system on board the shuttle.
This post:
www.abovetopsecret.com...
tells us which camera.

I don't consider saying someone lacks understanding to be an insult. But I do consider being called and idiot to be.

[edit on 11/28/2009 by Phage]



posted on Nov, 28 2009 @ 05:52 PM
link   
reply to post by Arbitrageur
 



Then please explain this, why should someone calibrate the infinity setting on a high quality camera if there is no focal point.

All the information I have read confirms that a camera's infinity setting is the longest focal point of the lens. Are you saying this is not true?



posted on Nov, 28 2009 @ 06:34 PM
link   
reply to post by poet1b
 


Once more, please try to talk to someone that knows how these things work, this way you are not using your time in a productive way, you are mixing some of the things and making it harder for yourself to understand how things work.

About the cameras, if I remember correctly, they were analog cameras (using tubes instead of a CCD), but I have to look for it.



posted on Nov, 28 2009 @ 09:34 PM
link   
reply to post by Phage
 


Well, then all I can say is when you make statements like you made in your post before last, it "makes one wonder if you understand anything of what you are talking about".



posted on Nov, 28 2009 @ 10:53 PM
link   
reply to post by ArMaP
 


What I do know is instrumentation, and in this field I am an expert, and a camera is an instrument. When a camera is set at infinity it is set at specific focal point, which, for high quality cameras, should be calibrated.

Things that are too far in front or two far behind the place where that point is focused on will be distorted. A camera always focuses on one point, and the depth of field is determined by that point, as well as the circle of confusion. SA does in fact happen both in front of and behind the focal point, even when the camera is set to infinity. The links I have provided show this clearly.

If you people don't get this, then maybe you simply do not understand the process. It is like a great many things, like advanced algebra, geometry, trig, calculus, physics, all that sort of stuff, programming C is another arena. Some people never get it, and some of us instinctively get it.

I will add that it looks like the camera being used in this video has a telescopic lens, and is not focused at infinity, as they zoom in even closer to the tether during the video. Also, it appears that the focus is being played with during the video, of course as well as the aperture.

In addition, most of the round dots floating or flying around the tether are as well focused as the tether. The link I provided on SA clearly shows what spheres look like in focus, and that is what we are seeing with most of these UFOs.

toothwalker.org...

Here is a link that clearly states SA can be seen when the camera is adjusted to infinity past the far end of focus at infinity.

www.kenrockwell.com...


In Existing Images

Look for points of light in the background. Perfect subjects for this are distant points of light at night or sometimes light shining through leaves or specular reflections in daylight.

If they all blend together nicely, that's nice bokeh. If they are perfect little circles, then that's neutral bokeh. If they are all swimmy and look little little rolled up condoms or donuts, then that's bad bokeh.

If they all are regular polygons that tells you the shape of the lens diaphragm. Yes, you can actually tell how many blades the lens's diaphragm had!

If they are perfectly round in the middle of the image and oval or lentil shaped at the sides that tells you the image was probably shot at full aperture.

If they are all flattened ellipsoids (vertical ovals about twice as tall as they are wide) then that tells you that the image was shot with an anamorphic lens. You'll see this in cinemascope motion pictures, not in still photographs.

In Your Lens

Find a point of light in the distance. You can do this easily at night by finding a distant point streetlight, or you can do it indoors by taking the reflector off of a Mag-Light flashlight and just setting it up on the other side of the room.

Now look at the ground glass as you focus. If you see perfect round disks your lens has neutral bokeh, if you see soft-edged shapes you have good bokeh, and if you see doughnuts you have bad bokeh.

If you see something other than neutral bokeh you'll see the quality of the bokeh change as you focus both in front of and in back of the point of light. Of course you can't usually focus beyond a distant point of light, unless you have a view camera or a lens that allows focusing beyond infinity.


Now your claims about bokeh have been proven false.

Edit to add add to quote


[edit on 28-11-2009 by poet1b]



posted on Nov, 28 2009 @ 11:12 PM
link   
reply to post by jackphotohobby
 


What really doesn't?

You don't address the point of difference here. Let me ask you the questions directly.

When focus is set to infinity on a camera, is there a focal point?

Does SA occur at distances beyond the depth of field of the infinity setting?

Is the article I linked to above on the subject wrong?

Can anyone provide a link to back up this claim about SA with focus set at infinity?

Oh, yeah, I looked at a couple of pages of those photos, they all look like distortions, or intentionally created camera effects. Can you provide a singe photo that looks anything like what we are seeing in this tether video. You would be the first.



posted on Nov, 29 2009 @ 01:49 AM
link   

Originally posted by poet1b
reply to post by Arbitrageur
 



Then please explain this, why should someone calibrate the infinity setting on a high quality camera if there is no focal point.

All the information I have read confirms that a camera's infinity setting is the longest focal point of the lens. Are you saying this is not true?



Your information is correct, infinity is the longest focal point of the lens. But you apparently didn't grasp what I said about infinity being the setting for parallel light rays and all the implications that ensue from that.

At any distance closer than infinity, the light rays are diverging. At infinity (near infinity like a star) the light rays are parallel. That's why the adjustment stops at infinity, because the light rays are either diverging, or parallel. They are never converging (The possible exception is gravitational lensing which may cause slight converging of the light rays of distant galaxies with large masses bending their light rays, but only astronomers care about that, camera lens manufacturers assume parallel is the furthest possible).

So your question infers you are thinking of focal point as something that is continuously adjustable, but basically the adjustment just stops when the light rays become parallel. For the cameras aboard the space shuttle, the tether light rays in the subject video may be considered effectively parallel, it would take a telescope instead of a camera to consider them otherwise. Therefore anything further than the tether may also be considered to have parallel light rays, and there is no further focal point than infinity.

There is a focal point on the camera's imaging system for infinity (the film or CCD), but there is no corresponding focal point in space in front of the camera like there are for all other focus settings besides infinity. The reason is the parallel light rays, which correspond with infinity, have no apparent distance in front of the camera other than infinity. Read that last sentence again, it's important and I think it's the point you don't get.

Here's an explanation that correlates infinity focus and aperture with the circle of confusion:

www.largeformatphotography.info...


Infinity is when the light rays coming from the object you are photographing are parallel. Practical infinity is when they are so close to parallel, you can't tell that they're not. Like most things, you have to decide how closely you want to look.

The simplest thing for photographers is to assume that the defocus of an object at infinity is acceptable if the defocus disc is equal in size to the circle of confusion. Infinity is then just the hyperfocal distance:

infinity = (focal length)^2/(f-number * c.o.c.)

That's pretty blurred. A more stringent criterion is to make the defocus equal to the diameter of the Airy disc - essentially you are saying that diffraction limits your ability to detect parallelism. If you measure the focal length in millimeters infinity in meters is given by:

infinity = 0.75 * (focal length/f-number)^2

For a 150 mm lens at f22, the first formula gives about ten meters, the second about thirty five.


I think the shuttle camera in question had a focal length from 18 to 108mm and I'm guessing at one point it was zoomed into the max at 108mm to get the best view of the tether, though I'm not sure of that. The F-stop or aperture ranged from f1.6 to f16. Since the image is overexposed I'm biased to think maybe a lower f-setting was used rather than a larger one, but I really don't know the F-stop setting used, so let's plug in both extremes using the more conservative (airy disc) formula for sharp focus:

at f 16: 0.75*(108/1.6)^2 = 34.17 meters
at f1.6: 0.75*(108/16)^2 = 3417 meters

So at those F-stop settings, anything that distance or greater should be in focus when the focus is set to infinity. If you want to allow slightly more fuzziness in the less conservative "circle of confusion" formula, it's about 1 kilometer or more at f1.6 to be in focus at infinity. This is why I've said in previous posts that the bokeh objects are closer than one kilometer, and probably much closer, because if they were, say, 900 meters away, they would be only a little fuzzy, and not great big bokeh like we see.

Note there is no upper limit, any distance further than that will be in focus when set to infinity.

[edit on 29-11-2009 by Arbitrageur]



posted on Nov, 29 2009 @ 03:23 AM
link   
reply to post by Arbitrageur
 


Um, no, sorry, and your link doesn't back up what you say.

Light rays from any source do not travel parallel. They diverge out from a single point in an ever expanding circle. What a lens does is reverse this process, which is why focus is important. The light reflected off of the subject is diverging, expanding in an ever increasingly larger circle. When it goes through a lens, the diverging light is then converged, and if the capture device is at the right distance from the lens, the image of the light source is accurately captured.

When the light source is too far away, then the curvature of the lens does not succeed in converging the diverged light adequately enough to focus the image properly on the capture device, be it film or a wafer, and the image looses detail.

The infinity setting is just the maximum capability of the lens to converge what is diverging. Anything farther out than the capability of the lens never converges enough to create an acceptably focused picture. Not only would the capture device have to be further away from the lens, the capability of the lens to curve the light would have to be superior to better capture the image. The further out the subject, the grainier, and more blurred the picture. You have this expanding ring of distortion, and distortion is the correct term here.

Here is another link which explains it somewhat.

www.usa.canon.com...

The further away the object which is reflecting the light, or producing the light, the smaller the slice of pie the lens has to work with. This requires the precision at which the light changes direction to be far more accurate for good results, which requires wider curves that must be much more uniform in their arc.

I took a couple of pictures of the moon with my camera, and your can clearly see the bokeh. I will try to insert them into the thread. It will be a first time I have attempted this. I guess I must choose a host for the images. My camera was set to infinity. Apparently my lens delivers pretty bokeh.



posted on Nov, 29 2009 @ 07:09 AM
link   

Originally posted by poet1b
What I do know is instrumentation, and in this field I am an expert, and a camera is an instrument.
What we are talking about is not the camera, is the lens.

Aperture, focal length and focusing all happen within the lens, the camera only deals with the image presented by the lens.

In an electronic camera (either photo or video), the embedded electronics can then change the effects of the light entering the camera, like with an automatic or manual gain system, to further compensate for low light levels.


When a camera is set at infinity it is set at specific focal point, which, for high quality cameras, should be calibrated.
When the lens is set to infinity it means that the internal lens elements are positioned in a way that the lens show all objects further than a specified distance focused. That distance is specified by the lens construction.


Things that are too far in front or two far behind the place where that point is focused on will be distorted.
But the whole idea of being focused to infinity is not to have a too far behind point, when focused to infinity a lens shows all objects further than the specified distance in focus.

That's the same thing that happens with our own eyes.

If you extend your arm and focus your vision in your hand you can see that the objects that are behind it look out of focus and that at half the distance to your hand, for example, things are also out of focus.

If you focus your vision to an object some 15 metres away you will see that things closer than that are out of focus and that things that are much farther away are also out of focus.

And finally, if you focus your vision to an object that is some 50 metres away you can see no difference in focus between that object and an object 2000 metres away.

Using the above numbers, that would mean that your eyes would be focused to infinity when focused to something at 50 metres away or more, and only closer objects will look out of focus.

All those numbers above were chosen just by looking out the window.



If you people don't get this, then maybe you simply do not understand the process.
Think of it this way.

I would start talking about instrumentation, and would provide several pages that, although with the right information, were not enough for me (or I wasn't able, for some reason) to make me understand the basis of it all. As I could not understand the basis, I would make a wrong interpretation of the information available on the pages and would presented it with some things mixed with other, directly unrelated things.

What would be happening then, it would be you, someone that knows all about instrumentation, that was wrong, or me, as someone that had not grasped the basis of it, that was wrong and not understanding the process?

What would you suggested I did in a case like this?

Would you suggest that I should stop thinking about it and would ignore what I was saying because I was only making a fool of myself?

Would you suggest I should re-read the same pages from where I got the wrong interpretation, with very little possibility of the right interepretation being done on the already read information?

Or would you suggest that I should talk to someone that could explain it better in person, instead of trying to explain it with links to pages and graphs and images?

I chose the last option because I think that you are intelligent enough to understand it all but you need someone to explain it to you where you are moving away from the correct interpretation, someone that would say "stop right there, you are going the wrong way" when you were saying something, and we cannot do that with a medium like this, in which all our communications are sent in block with no "handshaking" to ask to repeat the data or interrupt the process.


It is like a great many things, like advanced algebra, geometry, trig, calculus, physics, all that sort of stuff, programming C is another arena. Some people never get it, and some of us instinctively get it.
My favourite is assembly programming, it's much more interesting.

And don't worry, I think you will eventually get it, if you stop thinking that we are all just thinking about proving you wrong.


Just be patient.


Also, it appears that the focus is being played with during the video, of course as well as the aperture.
That's something I always thought, how could they know that they had the camera really focused on an object like that?


Here is a link that clearly states SA can be seen when the camera is adjusted to infinity past the far end of focus at infinity.
Really? Where does it say that?

PS: I am far from a photography expert, there are many things that I do not understand myself, but when I want to know something I ask someone that I know really knows about it.



posted on Nov, 29 2009 @ 11:56 AM
link   

Originally posted by poet1b
reply to post by Arbitrageur
 

Light rays from any source do not travel parallel.


O really? Let's see what I posted about parallel light rays.


Originally posted by Arbitrageur

www.largeformatphotography.info...


Infinity is when the light rays coming from the object you are photographing are parallel. Practical infinity is when they are so close to parallel, you can't tell that they're not.


So let's see how you support your claim that light rays aren't parallel, by posting a link. Let's see what this link says:


Originally posted by poet1b
Here is another link which explains it somewhat.

www.usa.canon.com...α=DEF


And I open the link and what do I find? A diagram showing parallel light rays, supporting my point, and refuting yours:



When you post links that refute your own claims and support the one you are arguing against, it highlights the fact that you are displaying ignorance about the subject of photography by reading a few things, not fully comprehending them, and then using what you read to argue with people that have years of real experience with photography. I was expecting better from you after you were able to admit the truth about the sublimation of ice in space, that showed real intelligence.

But claiming light rays aren't parallel and then supporting your argument by posting a link with a diagram showing parallel light rays, is not showing the same perception as you showed regarding ice sublimation, or maybe it is, as I recall you took quite a bit of convincing on the sublimation topic too before you admitted you were wrong. You're wrong on this topic too and the sooner you admit it, the more intelligent you'll look, once again.

[edit on 29-11-2009 by Arbitrageur]



posted on Nov, 29 2009 @ 12:23 PM
link   
reply to post by Arbitrageur
 


The parallel light rays are supposed to represent everything that is going into the lens, but it isn't accurate, but that doesn't matter to this discussion.

What is relevant to this discussion is the second diagram, which clearly shows the light from the object which is the subject, like the tether, or the moon, or something like that. The light from the subject or object is diverging, not parallel, just as I explained.

Here is a picture of the moon taken with my camera set at infinity. As you can clearly see, the moon is complete bokeh.





Seeing is believing. Clearly we have bokeh beyond the field of view of the infinity setting.

Edit to add larger image of the moon.

[edit on 29-11-2009 by poet1b]

[edit on 29-11-2009 by poet1b]



posted on Nov, 29 2009 @ 12:42 PM
link   
reply to post by poet1b
 


The parallel light rays in that first diagram couldn't be any more relevant. The camera lens is unable to distinguish between real infinity and practical infinity when the source is far enough away. The first diagram shows that when the camera lens focuses at infinity, there's only one focal point on the camera side of the lens because the light rays coming in are parallel or so close to it the difference cannot be detected by the photographic equipment.

The 2nd diagram shows how the camera focuses on other focus points closer than infinity, and shows there's a focal point on both sides of the lens, versus only the camera side in the first diagram.

Even confronted with facts from your own source staring you in the face, rather than absorb the information, you go into denial and say it's not relevant?



posted on Nov, 29 2009 @ 01:45 PM
link   

Originally posted by poet1b

Here is a picture of the moon taken with my camera set at infinity. As you can clearly see, the moon is complete bokeh.



Seeing is believing. Clearly we have bokeh beyond the field of view of the infinity setting.


That is a picture of the moon which is out of focus.
If you really manually adjusted focus to infinite, and get this, then i tell you, your camera is NOT WEL calibrated! Ask the experts!


My >3year old camera Canon S2 IS 5 megapixel photocamera is very well calibrated. When i select infinity, and i do this as a rule when i'm sure from experience that the automatic focus could be fooled, so, when i select infinity, i get clear focus of the bird 300 meters away, or of the plane 8 km away, or of the mountain/landscape 30 km away, or of the moon 380000km away, or of the Pleiades constellation hundred of light years away.

My older film camera, a russian Zenit SLR camera, with interchangeable lens, which now rest in peace being too old....when i set manually the focus on infinity, no matter my normal 55 mm lens, or my 200 mm tele-lens, i get infinity in focus.


My last camera, a Panasonic High definition model, SD5, when i set focus manually to infinity, i obtain slighty out of focus images...bad thing...it is a bit uncalibrated...but it was one of the cheapiest models.


So, if really your camera, when manually set to infinity produce that out of focus image, it means also is uncalibrated. Ask the experts again, regarding this, don't rely in only what is good for your ideas.



posted on Nov, 29 2009 @ 02:15 PM
link   
reply to post by depthoffield
 


No, my camera is a pocket camera which simply doesn't have the range to take a picture of the moon and get any kind of detail, so it blurs everything.

You only think you get clear focus. Take a picture of the same landscape with a far better camera, then download both pictures onto your computer, and zoom in on a small detail. You will see that the better camera has better resolution.

You are also probably talking about good lighting conditions. Try taking a picture of that bird into almost direct sunlight, with the sun in the frame or just out of the frame and see what you get.



posted on Nov, 29 2009 @ 02:28 PM
link   
reply to post by depthoffield
 


Yes, poet's camera is either uncalibrated at infinity, or else it's not a very good camera or lens. I'm amazed at how many $200 cameras have junky lenses.

Poet you didn't give us the specifications of your camera and lens, which might help in assessing the quality of photo to expect. As I said before, I have good cameras, and bad cameras, and good lenses, and bad lenses, the quality of pictures they take varies greatly, so it could be the quality of the equipment as well as the calibration of the infinity focus being off.

I have one zoom lens in particular that doesn't stay focused at infinity throughout the entire zoom range like it's supposed to, thus the calibration of infinity focus on that lens depends on what zoom it's at. If I had spent a lot more money for a better lens, I probably wouldn't have to tweak the infinity focus. I've never had infinity out of calibration on a fixed focal length lens, but that doesn't mean it can't happen.



[edit on 29-11-2009 by Arbitrageur]




top topics



 
77
<< 97  98  99    101  102  103 >>

log in

join