New Analysis Video of the STS-75 Tether Incident

tether spotted in the sky






reply to post by ArMaP

oops , sorry ArMaP i made a mistake and read the post wrong

[edit on 26-11-2009 by easynow]

reply to post by ArMaP


But your knowledge of video is clearly not superior to mine, if it was you would not say that photography and videography are the same, especially when it comes to this situation. Let me explain why.

A photo only needs to have the focus and the aperature, which is the problematic adjustment in this situation, set up for the short period during which the shutter is open and the photo is captured. The distortions are only acting upon specific areas which will be consistent in a photo.

In a video, the camera is constantly recording visual images, which means that the light intensity is constantly changing, especially in this video in which it is probably the most critical factor, which results in a constantly changing arena of distortion. If you can wrap your mind around this concept, then you will realize that the two are very different. In a video rapidly changing light intensity creates most of the distortion, and that is what we are seeing in the tether video.

I am not the only one who needs to learn more about this subject. As the guy who wrote the articles I pointed out explains numerous times, there are a great many variables. As I have pointed out, there are too many variables for the claims that you are making.

Yes, there is considerable reason for the videographer to have experience with videos taken in space because the brightness and contrast are far more extreme, and tend to be the most difficult things to deal with.

Um, I have been pointing out the role of the aperture for a long time now, and your side has been ignoring this critical role, just as you ignore the overexposure that is creating most of the distortion.

By the way, I know a great deal about the relationship between temperature and pressure in vapor and gas volumes, that's why I assumed something that was wrong. Normally I would have checked my facts. I am still astounded by the way ice forms in space. I think the physics implications are astounding. It seems that in a extremely low heat environment, the attraction between particles increase, or at least the attraction between water molecules increases.

Originally posted by poet1b
reply to post by wmd_2008

 

Nice of you to finally figure out that bokeh is a general term after I provide a link to a sight that clearly illustrates this point. We have been making fun of your side for over twenty pages now for using this term like a kid in Jr High who has discovered a new word. What is clear is that despite all your claims, your horribly amateur video tapes, and use of words that you do not understand, is that none of you are experts on photography, so please stop trying to pretend differently. At least I have taken the time to look up what we see in the video which is more than any of you have succeeded in doing.

Lets take your statements, and insert some reality.

On this point your are starting to understand what is going on here.

Taken like this only objects a short distance either side will be in focus.

The part you are missing is that "objects a short distance either side" OF THE FOCAL POINT "will be in focus".

Let see I bought my first SLR CAMERA in DEC 1979 manual camera no auto focus no auto exposure SO I think I know more than you think.

So I will explain to you and others in simpler terms even you will understand you post things on photo web sites which

a) DONT back up your claims

AND

b) Are now going to make you look an IDIOT!

Re your above statement WHEN a lens is focused on infinity, the focus point is INFINITY so guess what you CANT have an out of focus area behind it.

IF you bothered to look at the DOF table for the lens you would see that, thats if you could actually understand the table!

link given earlier DOF table link on right side halfway down

www.sigmaphoto.com...


NOW LETS EXPLAIN THE INFORMATION ON IT TO YOU SO YOU DONT HAVE TO THINK!

PAGE 1 24mm focal length setting on zoom set to f2.8

when set to infinity rear focus is WOULD you believe infinity front focus point
6.464 mtrs so anything further than 6.464 mts to INFINITY ARE IN FOCUS

If the lens is focused at 3.00m f still 2.8 rear focus point 5.390 mtrs front is
2.103 mts what this MEANS is anything between 2.103 mts and 5.390 mtrs looks in focus anything either side will be OUT OF FOCUS.
This is what you would do to take say someones portrait to throw the background out of focus.

Now check out the other apertures for 24mm when focused at infinity now do you see how these BOKEH cant be at far from the camera or at the distance of the tether or behind it


Then look at the other focal lengths for this zoom lens then check others like I said!

WHAT you did not take into account the object on that site was CLOSE to the camera thats why it could have an area behind it out of focus.

So just to recap WHEN ANY LENS is focused on INFINITY any of these out of focus objects must be CLOSER than the FRONT focus point or they would be in focus.

ITS A PROPERTY OF LIGHT AND OPTICS!!!!!

[edit on 26-11-2009 by wmd_2008]

reply to post by poet1b

I understand that video is different, being a fast sequence of photos without the possibility of adjustments for each image, and I have no problem admitting the possibility of knowing less than you about video.

But don't you agree that the way light enters the lens from one side and exists on the other is the same, regardless of it being a photo or a video lens?

Or is there any difference in the lens for a video camera?

PS: I suppose that the lack of adjustments (like those we can do in photography) for each frame is one of the reasons they invented the automatic gain, and it can be fast enough to compensate for small changes from frame to frame, but I don't know (or at least I don't remember) how the shuttle cameras work or even if they had any automatic gain system.

So, do all of you who support the small particles near the shuttle agree with wmd_2008?

Set your camera to infinity and it can take clear pictures no matter how distance the subject is, it will always be within acceptable sharpness, there will be no distortion?

Or could it be that the infinite setting only refers to the camera's maximum range of focus, the point beyond which the camera can no longer take clear, acceptably focused pictures?

Other factors will not come into play, like changes in the amount of lighting, movement, all that stuff?

Lets say you take your phone cam which is a fixed focal point set at infinity. You take a picture with a lot of contrast, some very bright objects in the field of view, all at a long distance, say a 1.000 meters. Will there be distortion in the picture that is not close up distortion?

Then what about zoom. They obviously zoomed in on the tether. What does that say about what focus setting they might have used?

Do we have a consensus on the other side of this debate?

I will take lack of response as a consensus.

edit to change "maximum range or focus" to "maximum range of focus"


[edit on 27-11-2009 by poet1b]

reply to post by ArMaP


I would agree that the way the light goes through the lens is the same.

The setting of the aperture, however, is very different.

Would you agree that the setting of the aperture has a very critical affect on distortion, or in other words, brokeh?

If your image is in focus, but the amount of light changes drastically, if you do not change your aperture size, will you get distortion of the image?

What does your sister say about this?

Originally posted by poet1b

So, do all of you who support the small particles near the shuttle agree with wmd_2008?

Set your camera to infinity and it can take clear pictures no matter how distance the subject is, it will always be within acceptable sharpness, there will be no distortion?

No. The ability to resolve detail at distance it also dependent on the ability of the lens to resolve detail at a given aperture. Many of even my best lens will produce slightly soft corners and edges at large apertures. Lens manufacturers measure MTF:

www.luminous-landscape.com...

Now, to complicate things a little, the recording medium (whether that's a sensor, or film) also has fundamental limits to the detail it can resolve. On top of that a high-contrast picture may appear sharper than a low-contrast picture with more details.

Also, set at infinity, the hyperfocal distance is important:

en.wikipedia.org...

Now, on top of that , most lens have some degree of distortion, especially zoom and wide-angle lenses. Then there's stuff like chromatic abberations and vignetting .

Most of this stuff is quite well documented because people have been photographing for over 100 years now.

'Distortion' is a term that is a bit too broad to address specifically because there's different kinds of distortion.

reply to post by easynow


Cool video, thanks.

That thing really scoots across the sky.

reply to post by jackphotohobby


Thanks for the input.

I keep trying to point out that a great deal more things come into play than focus.

Specifically we are looking at Spherical Aberration, which is common and is seen before and after the focal point.

The claim seems to be that at the infinity setting, there is no focal point.

I am looking for consensus on this from the other side of the debate.

Originally posted by poet1b
Set your camera to infinity and it can take clear pictures no matter how distance the subject is, it will always be within acceptable sharpness, there will be no distortion?

No, it will take photos in which objects at a distance that is considered as infinity for that lens (or a bigger distance) are focused. Objects closer than that distance will be out of focus.

Or could it be that the infinite setting only refers to the camera's maximum range of focus, the point beyond which the camera can no longer take clear, acceptably focused pictures?

No, it's a continuation of the other measurements. Some lens have the focusing distance marked on them, something like "0.5 m", "2 m", "5 m", "10 m", "∞". From that point onwards it does not make a difference, the lens will "see" all things farther away in focus.

Other factors will not come into play, like changes in the amount of lighting, movement, all that stuff?

Not exactly, although those things affect the sharpness of the object in the image they do not affect the ability to focus on the object.

Lets say you take your phone cam which is a fixed focal point set at infinity. You take a picture with a lot of contrast, some very bright objects in the field of view, all at a long distance, say a 1.000 meters. Will there be distortion in the picture that is not close up distortion?

The bright objects may appear as overexposed, but I don't see what other type of distortion can happen.

Then what about zoom. They obviously zoomed in on the tether. What does that say about what focus setting they might have used?

As far as I know (from my own experiments) the change in zoom only affects the focusing when the camera is focused to a very short distance, something like 0.5 metres.

How about you Dof, any comments?

ArMap, what about "acceptably focused" pictures?

A person a km away on your cell phone, is that acceptably focused?

Or a big blur?

Originally posted by poet1b
Would you agree that the setting of the aperture has a very critical affect on distortion, or in other words, brokeh?

The aperture affects the distance in which the objects appear focused, smaller apertures give a bigger depth of field.

If your image is in focus, but the amount of light changes drastically, if you do not change your aperture size, will you get distortion of the image?

I get overexposure, that does not look the same.

I didn't got the opportunity to ask my sister about it.

Originally posted by poet1b
A person a km away on your cell phone, is that acceptably focused?

I don't know, I don't have a cell phone.

A fixed focus lens will be focused to infinity, so a person 1 km away will be on focus, but something focused may not look good because of lack of definition and other problems that happen with cheap lens.

That's why the cheaper lens possible (a pin hole) is theoretically very good in depth of field, but very hard to do well, so it's hard to have good, well defined, pin-hole camera photos.

Originally posted by poet1b
So, do all of you who support the small particles near the shuttle agree with wmd_2008?

Set your camera to infinity and it can take clear pictures no matter how distance the subject is, it will always be within acceptable sharpness, there will be no distortion?

Or could it be that the infinite setting only refers to the camera's maximum range of focus, the point beyond which the camera can no longer take clear, acceptably focused pictures?

Other factors will not come into play, like changes in the amount of lighting, movement, all that stuff?

Of course spherical aberration, motion, lighting, aperture and other factors all come into play in determining how sharp an object is. But, if your question is meant to suggest that those effects could explain why the donut shaped bokeh we see is really further than or the same distance as the tether, then the answer is that other effects you are considering such as spherical aberration and motion blur do not produce that donut shaped bokeh, that is a result of out of focus caused by a combination of the focus setting (which determines the focal point) and the aperture, which determines the depth of field or what range of distances will be in focus.

Each effect has its own signature, for example motion blur of a moving dot forms a streak that's elongated in the direction of the motion, or other effects that can occur in video such as temporal strobing, etc.

I have many cameras and many lenses. I've noticed spherical aberration varies a lot by what camera I use, and how good the lens is at correcting spherical aberration, and whether it's a zoom lens or not. I can set two similar cameras at infinity and take similar pictures and the one with the better lens has less spherical aberration and is sharper. In other words using a cheap crappy lens will give worse results than a good lens and I have some of each. I've also noticed zoom lenses often have more difficulty correcting for spherical aberration than fixed lenses.

I think of infinity focus setting on a camera in terms of geometry, trigonometry and resolution. An object at almost true infinity like a star will have for all practical purposes parallel light rays. The light rays coming from closer objects are not parallel. So the infinity setting is really just setting the focus of the lens for parallel light rays. If I install a wide angle lens focused at infinity,even relatively close objects (say 15 feet away) appear in focus because the lens can't distinguish much difference from parallel on the closer objects. But installing a telephoto lens renders the object at 15 feet away out of focus when it's set to infinity, because that lens can distinguish smaller angular differences in the light rays due to its higher magnification.

Just to reinforce spherical aberration doesn't have to be significant at infinity, here's a photo of the Soul Nebula taken by an amateur photographer, and the stars look pretty sharp for amateur equipment, though you could get better at a world class observatory.

blog.deepskycolors.com...

The stars aren't perfectly sharp in that photo but they're pretty clear. As this photo shows, you can take clear pictures of stars using an equatorial mount so there's no reason to think that even stars are beyond the maximum focus range for a camera lens. Just think of infinity focus as a parallel light ray setting, there's no maximum distance involved.

How sharp the object is can be affected by many other things, but after focus, (and the aperture effect on focus) I would say primarily equipment. I expect the cameras aboard the shuttle are pretty good (at correcting spherical aberration, at least compared to some cheaper cameras).

Edit to add photo.

[edit on 28-11-2009 by Arbitrageur]

reply to post by Arbitrageur


Sounds like photography is your hobby. It is not mine, but I am a quick study. I have taken my fair share of pictures, and do have a video camera, and of course have watched many videos.

That is a nice photo, but even in that photo we are seeing SA. Doesn't shutter speed also come into consideration? Shutter speed is not a luxury which video shares. Film speed is the manner which video deals with shutter speed, but it is far more technical. This tether video isn't exactly set up as a prime example of exemplary video technology.

From what I see in this tether video, once the tether comes into view, nothing is within acceptable limits of focus. It is all distorted. What then is the depth of field?

Originally posted by poet1b
From what I see in this tether video, once the tether comes into view, nothing is within acceptable limits of focus. It is all distorted. What then is the depth of field?

no, not all are "distorted". For example many of the stars are not distorted.

Tether is distorted, because is overexposed, making it to appear thick, while theoretically it should appear exactly 1 pixel in thickness (because the pixel is the smallest unit creating the image).
While overexposed and having more pixels in thickness instead only one, also blooming is another effect acting on the image of the tether, making inner surface to be grey, darker than it's borders.

Similar, bright stars (like Menkent) or bright debris (when lens is unzoomed) doesn't appear as only a pixel, but also bigger, and more like a horizontally stretched shape...becaue overexposure and also blooming of inner surface appear in some cases.

But the big discs with dark center and notches, while of course subject to some of the same distorsions, are clearly (and doubtless when people act in informed manner with some experience gathered) real shapes produced by the lens....real shapes produced by the lens, but NOT real disc-objects, but only what the lens can produce in out of focus situation which is BOKEH.


Asking to your question, Poet1b, "what is then depth of field", (because i see your strategy to present the tether images as being very bad, without depth of field, full of complicated distorsions non-understandable for common people, therefore worthless for any analysis ...which analysis clearly shows evidence for smaller and closer objects) here is some very good explanations:


Depth of field and factors influencing it:

Part1: www.youtube.com...

Part2 (circle of confusion): www.youtube.com...

Part3: www.youtube.com...

Part4 (hyperfocal distance): www.youtube.com...

Part5: www.youtube.com...

Part6: www.youtube.com...





further links:


Some basics: www.idigitalphoto.com...

en.wikipedia.org...

About BOKEH:
en.wikipedia.org...
www.rickdenney.com...
www.bokehtests.com...

another tutorial:
part1: www.youtube.com...
part2: www.youtube.com...
part3: www.youtube.com...
part4: www.youtube.com...
www.youtube.com...
www.youtube.com...








[edit on 28/11/09 by depthoffield]

reply to post by depthoffield


It is not too complicated to understand, it just shows that claims that the hollow center SA must be a few meters away are not realistic. The evidence also shows that the dots that are solid are most likely near the tether. It all depends on what the depth of field is.

Here is an article that explains it pretty well.

www.cambridgeincolour.com...

Originally posted by poet1b
It is not too complicated to understand, it just shows that claims that the hollow center SA must be a few meters away are not realistic.

Could you please explain what do you mean by that?

Thanks.

reply to post by ArMaP


The link I provided on Spherical Aberration a page or two back covers this fairly well.

Here is another link on the subject. Most of these about about getting good bokeh, so they don't explore eliminating bokeh, or aberration, in space, or aberration produced at the infinity setting.

www.bobatkins.com...

reply to post by poet1b


It really doesn't. If anything it emphasises that the optics provide a good explanation of what's going on. It back up everything Armap, DoF, etc. have been saying (nb: I've excluded important contributors for brevity, and the context of this page in the thread). Spherical aberrations/bokeh of small objects close to the lens is why people post similar theories about 'spirit orbs'. It makes photographers laugh.

Check out:

images.google.co.uk...

Maybe if ghost hunters had a similar lenses to Nasa there'd be extensive debate about whether spirits were extraterrestrially piloted... And people go to similar lengths to try and validate those. It's a shame.

Come to think of it Casper The Friendly Ghost does look like he could be a grey alien.