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Author Topic: The Physics of Digital Cameras  (Read 39945 times)
WarrenMars
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« on: December 18, 2009, 06:06:12 PM »
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Think you understand the theoretical basis for Digital Cameras? ...  
Unless you have done the figures on Poisson aliasing I'm betting you don't.
Only a proper understanding of the physics of digital cameras and how they match the parameters of human visual perception will show you where the limits of camera technology lie.

You may be suprised to find that current image quality is already within 2 stops of its theoretical maximum and is unlikely to improve by more than 1 stop. You may also be surpised to discover that current technology has already pushed photography 6 stops beyond what can be achieved theoretically and that the difference has been covered up with a combination of human tolererance, noise reduction and sharpening.

There may be some other results that may surprise you also. Go ahead and read my exposé on this fascinating and complex subject. I don't think you'll find this stuff anywhere else on the net, no doubt the big companies know it all but they keep their secrets to themselves.

http://warrenmars.com/photography/technica...ion/photons.htm
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feppe
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« Reply #1 on: December 18, 2009, 06:42:55 PM »
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Quote from: WarrenMars
You may be suprised to find that current image quality is already within 2 stops of its theoretical maximum and is unlikely to improve by more than 1 stop. You may also be surpised to discover that current technology has already pushed photography 6 stops beyond what can be achieved theoretically and that the difference has been covered up with a combination of human tolererance, noise reduction and sharpening.

I'll let those qualified to critique your theory and physics, but you yourself state that we've already gone 6 stops beyond what theory states. The obvious question is what makes you think further developments in hardware, noise reduction, sharpening and other post-processing techniques won't push the boundaries farther than one more stop of improvement? Sounds as compelling as Peak Oil, and just as hokum.
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tim wolcott
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« Reply #2 on: December 18, 2009, 11:35:38 PM »
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Quote from: WarrenMars
Think you understand the theoretical basis for Digital Cameras? ...  
Unless you have done the figures on Poisson aliasing I'm betting you don't.
Only a proper understanding of the physics of digital cameras and how they match the parameters of human visual perception will show you where the limits of camera technology lie.

You may be suprised to find that current image quality is already within 2 stops of its theoretical maximum and is unlikely to improve by more than 1 stop. You may also be surpised to discover that current technology has already pushed photography 6 stops beyond what can be achieved theoretically and that the difference has been covered up with a combination of human tolererance, noise reduction and sharpening.

There may be some other results that may surprise you also. Go ahead and read my exposé on this fascinating and complex subject. I don't think you'll find this stuff anywhere else on the net, no doubt the big companies know it all but they keep their secrets to themselves.

http://warrenmars.com/photography/technica...ion/photons.htm

I find this interesting, but this really is what is wrong about photography.  The art of teaching tech.  Its good to the practical limits of what you can do and achieve with your equipment.  However, true photography and the artist who see the best, compose the best, and choose the pre-visualization for the images they create, will always be the better photographer.

We have gotten so far away from this art of photography and instead of perfecting this art.  You are focusing on tech that cannot be really controlled unless you are making the equipment.  We are all subjected to equipment that has flaws,  I personally contact every manufacturer of equipment I use and ask and show what is wrong so I have a better piece of equipment to use and you do to.

Most photographers who want to get better should be focusing on the art of shooting it once and capturing it right the first time.

Granted we have better tools now than ever before, but the quality of the photographs are lacking at best.  This hit and miss style of just shooting and wondering what you captured is what is truly wrong with our industry.

Its easier to understand tech, its just knowledge and doesn't take that much effort.  Rather than studying what, where and how you are going to create your next great image.  I know I spend a tremendous amount of time doing this.  FAILUE TO PREPARE IS PREPARING TO FAIL.  

Still a 2 dollar framing card will do more for your composition than all the tech you can resolve in your brain.

The Masters that came before us must be laughing at most of us.  Tim Wolcott    www.galleryoftheamericanlandscape.com  
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PeterAit
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« Reply #3 on: December 19, 2009, 09:20:58 AM »
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Quote from: tim wolcott
I find this interesting, but this really is what is wrong about photography.  The art of teaching tech.  Its good to the practical limits of what you can do and achieve with your equipment.  However, true photography and the artist who see the best, compose the best, and choose the pre-visualization for the images they create, will always be the better photographer.

We have gotten so far away from this art of photography and instead of perfecting this art.  You are focusing on tech that cannot be really controlled unless you are making the equipment.  We are all subjected to equipment that has flaws,  I personally contact every manufacturer of equipment I use and ask and show what is wrong so I have a better piece of equipment to use and you do to.

Most photographers who want to get better should be focusing on the art of shooting it once and capturing it right the first time.

Granted we have better tools now than ever before, but the quality of the photographs are lacking at best.  This hit and miss style of just shooting and wondering what you captured is what is truly wrong with our industry.

Its easier to understand tech, its just knowledge and doesn't take that much effort.  Rather than studying what, where and how you are going to create your next great image.  I know I spend a tremendous amount of time doing this.  FAILUE TO PREPARE IS PREPARING TO FAIL.  

Still a 2 dollar framing card will do more for your composition than all the tech you can resolve in your brain.

The Masters that came before us must be laughing at most of us.  Tim Wolcott    www.galleryoftheamericanlandscape.com

Amen, bravo, and hear hear!
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Peter
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« Reply #4 on: December 19, 2009, 10:55:27 AM »
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Quote from: WarrenMars
From the bogus article:  "The reason you can burn objects with a magnifying glass is because where the rays meet is not in focus. They are in focus when they form an accurate picture of the sun, and that won't burn."

     
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HarryHoffman
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« Reply #5 on: December 19, 2009, 08:38:52 PM »
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I see on your site that your current camera is a D60 and you are happy with that. Have you tried anything better than that model to see what a real Pro camera can do for you?
Try a D3 or D3X and then try a Hassy or Phase One. These are not Hocus Pocuc cameras and are the real deal in terms of performance.
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Slobodan Blagojevic
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« Reply #6 on: December 19, 2009, 09:12:22 PM »
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Quote from: WarrenMars
... current image quality is already within 2 stops of its theoretical maximum and is unlikely to improve by more than 1 stop. You may also be surpised to discover that current technology has already pushed photography 6 stops beyond what can be achieved theoretically ...
I will immediately admit I am not qualified to debate the theory behind this, but I still find the above quote logically challenging. Are we within two stops from a theoretical maximum, or we are six stops beyond? For me, "what can be achieved theoretically" = "theoretical maximum", hence my confusion.

And ultimately, every time I hear a statement like that, it reminds me of the bumble bee paradox (i.e., that given our knowledge of aerodynamics, bumble bees are too heavy to fly).
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michael
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« Reply #7 on: December 20, 2009, 08:19:39 AM »
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When the link to this article was first posted I read the piece with some considerable interest, since there is little like it available online.

Much of the math and physics are beyond me, (though I saw quite a few things that appeared erroneous) so I forwarded the link to a couple of friends, one a Physics Phd and photographer with serious credentials, and the other a Phd who is heavily involved in the design of digital imaging systems.

It appears that though there is some good information in the article, there are also a lot of errors and misinformation.

"Some of his arguments do follow a more or less logical flow, but his pages strike me (not knowing anything about the guy) like he is an amateur scientist trying to explain a very difficult subject that he himself does not understand beyond a rather superficial level."

"He gets some things right but also quite a few wrong. In general his analysis lacks an abundance of technical details, which will contradict some of his conclusions."

So, I caution anyone reading Mr. Mars essay, that though it might appear comprehensive, it is flawed, with numerous erronious conclusions, at least according to real two experts whose opinion I do trust.

Michael
« Last Edit: December 20, 2009, 08:21:13 AM by michael » Logged
ErikKaffehr
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« Reply #8 on: December 20, 2009, 09:03:38 AM »
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Hi,

A good article discussing much of the same issue is here: http://www.northlight-images.co.uk/downloa...al_Limits_2.pdf

Regarding Mr. Mars essay I also found it a bit confusing and less than stringent. In my view Mr. Mars has a good point about Poisson characteristics of noise but I don't think that his finding are consistent with what we can see. Even if the content would be correct, the presentation is quite sloppy.

Best regards
Erik



Quote from: michael
When the link to this article was first posted I read the piece with some considerable interest, since there is little like it available online.

Much of the math and physics are beyond me, (though I saw quite a few things that appeared erroneous) so I forwarded the link to a couple of friends, one a Physics Phd and photographer with serious credentials, and the other a Phd who is heavily involved in the design of digital imaging systems.

It appears that though there is some good information in the article, there are also a lot of errors and misinformation.

"Some of his arguments do follow a more or less logical flow, but his pages strike me (not knowing anything about the guy) like he is an amateur scientist trying to explain a very difficult subject that he himself does not understand beyond a rather superficial level."

"He gets some things right but also quite a few wrong. In general his analysis lacks an abundance of technical details, which will contradict some of his conclusions."

So, I caution anyone reading Mr. Mars essay, that though it might appear comprehensive, it is flawed, with numerous erronious conclusions, at least according to real two experts whose opinion I do trust.

Michael
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JeffKohn
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« Reply #9 on: December 20, 2009, 01:06:45 PM »
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Quote from: slobodan56
I will immediately admit I am not qualified to debate the theory behind this, but I still find the above quote logically challenging. Are we within two stops from a theoretical maximum, or we are six stops beyond? For me, "what can be achieved theoretically" = "theoretical maximum", hence my confusion.
I was wondering the same thing, seems rather contradictory.
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Jonathan Ratzlaff
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« Reply #10 on: December 20, 2009, 03:41:55 PM »
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The solar flux levels you quoted for energy from the sun includes all areas of the spectrum, not visible light.  You need to revise your numbers to reflect the visible light spectrum,  ~400 - 700nm.  You then need to look at the attenuation levels of these wavelegths to earth.   You  are comparing apples and oranges in your chart.
The interesting thing is that the eye can visualize both objects lit by the noonday sun and the milky way wich by your estimation is  about 36 stops of light. although it needs to take time to adjust.  Instantaneously your eye can view about 20 stops again more than you state.

You may want to go back to your numbers and look at them more closely  

There have been a number of instances where theoretical limits have been exceeded.  When I was in university the limit of resolultion for light microscopy was about 200nm.  The theoretical limit to optical resolution was 1/2 the wavelenth of light being used to observe the subject.  however now we are at the 10-20nm resolution stage; an improvement of an order of magnitude.
Other examples, hard drive density, semiconductor density, quantum entanglement.

So don't place too much faith in theoretical limits; they are there to be broken.
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Bro.Luke
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« Reply #11 on: December 20, 2009, 07:43:42 PM »
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Son of "oh never mind...."
« Last Edit: December 21, 2009, 01:13:33 AM by Bro.Luke » Logged
kmanphoto
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« Reply #12 on: December 20, 2009, 08:05:46 PM »
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is actually reading this stuff  like the Flux Capacitor from the movie "Back to the Future" Huh
because if it is ----   oops  

kman
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Kent Whiting
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« Reply #13 on: December 20, 2009, 08:42:57 PM »
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Quote from: Bro.Luke
Ya know I stayed away from this forum...
And if you decide to revert to it, your enlightening and eloquent comments would be sorely missed.
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Slobodan

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« Reply #14 on: December 20, 2009, 08:59:27 PM »
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Quote from: PeterAit
Amen, bravo, and hear hear!
Amen and Bravo to someone who failed to notice that the op is talking about camera technology, and not about the good or the bad photographer?  
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WarrenMars
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« Reply #15 on: December 20, 2009, 09:15:28 PM »
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For those who are mystified by the apparent contradiction between 2 stops and 6 I apologise for not making it clearer. What I am saying is that technology has got within 2 stops of the best it can ever achieve in the future, meanwhile today's cameras are claiming speeds 6 stops in excess of what can be achieved even with perfect technology. There is no contradiction here. What I am trying to do is to make you think! The point is that the manufacturers are cheating by offering noisy, filtered images.

To all those who think that theoretical limits mean nothing, you can get back in your matter transportation device and travel faster than light back in time to the land where 2+2=5 and the sun shines in the middle of the night!

As for those who think technology is irrelevant: What are you doing reading this thread?

For those who think there are errors in my analysis: "Put up or shut up". Quoting some unknown friend who says: "He gets some things right but also quite a few wrong." is of no value.
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Jonathan Wienke
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« Reply #16 on: December 20, 2009, 10:28:38 PM »
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Quote from: WarrenMars
For those who think there are errors in my analysis: "Put up or shut up". Quoting some unknown friend who says: "He gets some things right but also quite a few wrong." is of no value.

Here's one blatant error:

Your discussion of standard deviations per level is completely nonsensical. You completely fail to recognize that as the photon count increases, you are increasing the sample population, and that decreases the standard deviation and increases the overall accuracy of the sampling (or confidence factor) by approximately the square root of the photon count. This is why digital images are noisiest in the shadows--the photon sample population per pixel is smallest in the darkest tones, and largest in the lightest tones. Your "Poisson Aliasing" chart seems to be assuming that the standard deviation increases (or at least stays constant) in proportion to average photon count as one increases the photon count, but this is completely backwards. As the photon count increases, the standard deviation decreases (at least when expressed as a percentage of the photon count) because you have a larger sample population of photons to work with. It's the same statistical principle used for calculating the margin of error for opinion surveys--the larger the sample population, the smaller the standard deviation becomes as a percentage of the sample population, and the greater the accuracy of the survey results becomes as a result.

If you were correct, the lighter tones in a digital image would be just as noisy or even noisier than the deep shadows. But this is the opposite of the behavior of every digital camera ever made. You need to go back and get the Statistics 101 stuff right before getting fancy with Poisson aliasing and stuff like that.
« Last Edit: December 20, 2009, 10:30:26 PM by Jonathan Wienke » Logged

Slobodan Blagojevic
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« Reply #17 on: December 20, 2009, 11:12:09 PM »
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Move over Ken Rockwell, the new king is here!  

The new king of hyperbole, oversimplification, overgeneralization, over-the-top opinionated arrogance... The new king of know-it-all, from quantum physics to corporate (im)morality. Smart people say that semi-knowledge is more dangerous than no knowledge... I now know what they mean.
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« Reply #18 on: December 21, 2009, 12:53:37 AM »
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Oh never mind...
« Last Edit: December 21, 2009, 01:12:48 AM by Bro.Luke » Logged
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« Reply #19 on: December 21, 2009, 09:45:16 AM »
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Always interesting to note certain stats when people make controversial statements.

OP post count = 2.  
OP Join Date = Dec 17, 2009

I'm just sayin...

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Fike, Trailpixie, or Marc Shaffer
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