# What is the typical DR for following?



## mukul (Mar 30, 2015)

1. A DSLR (FF or APS C)
2. An IPS/PLS LED Computer monitor, both standard and pro level
4. AMOLED display
5. and Human eye


thanks in advance


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## Marsu42 (Mar 30, 2015)

mukul said:


> 1. A DSLR (FF or APS C)



Muhahaha, that's a enterprising question to ask around CR :->. I'd say the typical dynamic range for a current dslr is ~14 stops on low iso (depends on sensor iq quality ), rapidly declining at higher iso. Lookie here: http://sensorgen.info/

I'm interested if anyone comes up with a valid answer for "human eye", that's a tough one as we're not digital!


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## takesome1 (Mar 30, 2015)

I think you need to define how old the human is. 

For that matter you might have to set ages for the DSLR and Monitor.

But the order is reversed. The newer DSLR's might have a wider DR than the older. The younger humans will probably have the wider DR.


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## IglooEater (Mar 30, 2015)

Cambridgeincolour puts the dynamic range of the human eye at around 10-14 stops. http://www.cambridgeincolour.com/tutorials/cameras-vs-human-eye.htm#sensitivity


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## privatebydesign (Mar 30, 2015)

The question isn't as simple as it sounds and the answers will, inevitably, be answering different ones.

They all react to the scene DR differently so drawing such blunt comparisons is not helpful. What would be helpful was if you gave the question context, i.e. What is the reason for your question?

For instance, the human eye can scan a scene with a massive DR but it can't actually see detail in both light and dark at the same time, but your brain can interpret those scans, effectively multi exposure blending. Or, for screen DR are you talking calibrated at a 'standard' brightness level or full screen brightness? Or for the camera, are you talking 'old time' DR, the difference between the lightest and darkest tones, or are you talking the modern interpretation of DR that cuts the dark tone value at the level they are swamped by noise?


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## Marsu42 (Mar 30, 2015)

IglooEater said:


> Cambridgeincolour puts the dynamic range of the human eye at around 10-14 stops.



Interesting, but they don't underly this with any research but it sounds rather like an educated guess by asking 'round the family:



> In that case, most estimate that our eyes can see anywhere from 10-14 f-stops of dynamic range



My personal guess would be subjective max. 10ev for the human eye because that's when hdr images start to feel "unnatural" as the dr is so squashed you'll never have the same impression like in real life.


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## takesome1 (Mar 30, 2015)

Marsu42 said:


> IglooEater said:
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> > Cambridgeincolour puts the dynamic range of the human eye at around 10-14 stops.
> ...



10-14 is a common answer around the net family. I have seen answers higher, one claimed 20 stops for the human eye.

But to PBD's comment about the brain blending, your eye has to adjust to do this. If you take this route one could say that the camera has a very wide DR. I have used my camera more than once to take shots in total darkness that I couldn't see my hand in front of my face. Long exposure, wide open aperture and have been able to get a picture of what can not be seen without a flash light. I have used this method several times at work to get images of items that I had to work on but could not see. So in that respect the camera has a much wider DR than the human eye, but poor or no ability to blend.


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## msm (Mar 30, 2015)

takesome1 said:


> Marsu42 said:
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10-14 is an estimate of what you can see at the same time. Give the eye time to adjust to light changes through change of aperture and chemical changes and the total dynamic range is somewhere around 20stops.

10-14 is way higher than a print or screen so in order too reproduce the same things as we can see with our eyes we need to push shadows to reproduce the same range. Fortunately our brain isn't that good at registering how bright different parts of the scene really are so it can be effective if done properly.


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## Andyx01 (Mar 30, 2015)

An IPS LCD display has a Dynamic Range of roughly 10 or 11 (see ANSI contrast ratio).

A better display (or print) would be required to view images at a higher DR and still appear natural as you put it.

The DR of a print would be limited by the INK's ability to obsorb light without reflecting it v.s. it's ability to reflect light, the amount of light present, and your acclimation to the sceen.

e.g. shine an intense lamp on black ink and it no longer looks very black. -or- shine an intese light on some black charcoal and hold it against the night sky for a reference point.

A display capable of high dynamic range would consume a tremendous amount of power and would look impressive.

Your eyes ability to 'see' dynamic range varies. (When you leave a bright area and enter a dark one, your range will be reduced until you acclimate. This is why pirates wore an eye patch.)






Marsu42 said:


> IglooEater said:
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> > Cambridgeincolour puts the dynamic range of the human eye at around 10-14 stops.
> ...


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## Andyx01 (Mar 30, 2015)

I think the total DR of the human eye is actually over 100 in terms of being able to descriminate luminance from night time shadows, to staring at the sun; but it's reportedly pretty low in a single scene in terms of a fixed pupil dilation and cone/rod saturation.

I think they say 6.5 stops - but that sounds pretty low. Who knows how they come up with it. Maybe they they dilated someone’s eyes and tested it 






msm said:


> takesome1 said:
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## Andyx01 (Mar 30, 2015)

mukul said:


> 1. A DSLR (FF or APS C)
> 2. An IPS/PLS LED Computer monitor, both standard and pro level
> 4. AMOLED display
> 5. and Human eye
> ...



1. DSLR's rate their Dynamic range, and it varies between sensors.
2. FF / APSC has little to do with DR, pixel size / pitch does however. (compare the 5D III to the 5Ds for example)
3. ..... hi
4. Contrast on AMOLED is excellent due to the min Luminance, DR will be dramatically reduced in a bright room or outside. So much so that LCD will appear to have more DR in the sun, while AMOLED will appear to have subsantially more in a dark room.
5. see Above.


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## PropeNonComposMentis (Mar 30, 2015)

privatebydesign said:


> ....
> For instance, the human eye can scan a scene with a massive DR but it can't actually see detail in both light and dark at the same time, but your brain can interpret those scans, effectively multi exposure blending.
> ....



Completely incorrect !


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## Marsu42 (Mar 30, 2015)

PropeNonComposMentis said:


> privatebydesign said:
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Care to elaborate?

Btw: THE MAN IS BACK (or someone else using the name) and strikes with quality content  ... I admit I was kinda curious after this thread: http://www.canonrumors.com/forum/index.php?topic=25697.msg506783#msg506783


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## PropeNonComposMentis (Mar 30, 2015)

Marsu42 said:


> PropeNonComposMentis said:
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Hi Marsu. Good to catch up with you.
Yeah, its me - still.
Before my account, images, and posts, were deleted ~mysteriously~, I had a reasonable long detailed post - explaining how the Eye works, how signals are dealt with by the Optic Nerve, and how the Brain distributes and priorities the information and processing.


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## geekpower (Mar 30, 2015)

correct me if i'm wrong, but i don't think it is possible for the human eye to scan a scene twice without a physical intervention to shield our eyes from the bright spots on one of the passes, and even then, the end result depends on our memory, and not our eyes...


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## Marsu42 (Mar 30, 2015)

PropeNonComposMentis said:


> I had a reasonable long detailed post - explaining how the Eye works, how signals are dealt with by the Optic Nerve, and how the Brain distributes and priorities the information and processing.



Pity ... one might think CR is all about repeating "crop vs full frame" discussions all over again, and then one posts that would be actually interesting gets lost :-o ... but hopefully someone else mentions some more insight into human "dr" w/o me taking the pain to google it myself.



geekpower said:


> correct me if i'm wrong, but i don't think it is possible for the human eye to scan a scene twice without a physical intervention to shield our eyes from the bright spots on one of the passes, and even then, the end result depends on our memory, and not our eyes...



I don't think so either, at least not with the same iris opening - and if that changes, it's essentially "bracketing".

But unless there's some sci-fi level tech involved, there's little telling what arrives from the optic nerve to the brain and how it gets processed (or not) afterwards. Even the "agreed upon" range of 10-14ev is *huge* so obviously people rather agree to disagree.


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## PropeNonComposMentis (Mar 30, 2015)

geekpower said:


> correct me if i'm wrong, but i don't think it is possible for the human eye to scan a scene twice without a physical intervention to shield our eyes from the bright spots on one of the passes, and even then, the end result depends on our memory, and not our eyes...


Go GeekPower !
The iris and retina can deal with all that, including your eye-lids. Blood flow to the retina is in a constant state of flux, and can shut-down 1 to 100 rods and cones in less than 1ms. The Cornier can move, and the fluid pressure in the eye can be altered.


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## privatebydesign (Mar 31, 2015)

PropeNonComposMentis said:


> privatebydesign said:
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Normally when people come back from a self imposed hiatus they do so without the attitude.

Anyway, my belief is that I am not _"completely incorrect"_, the retina has a DR capacity of around 6.5 stops; yet we can see detail in scenes with much greater DR than that because our eyes saccade (effectively scan) the scene, in doing so they very quickly adjusts the 'exposure' and our brain builds the complete picture. This is easy to demonstrate, just sit inside during the day and look out a window, now switch back and forth from looking to the inside and outside.

It is worth remembering, the really useful part of the eye, the fovea, only covers around 2.5º of vision, anything wider than that has dropped off the cliff for resolution, DR, colour, etc etc and is either made up by the brain or a reconstruction of something we already saw plus movement sensitive peripheral vision to aid in hunting and prevent being hunted.


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## nc0b (Mar 31, 2015)

In respect to the DR of the eye, age is certainly a factor. A few years ago three of us were in a car: me in my 60s, a father in his 50s and his son age 13. I was looking for 16th street, and was stopped at a traffic light. I said I cannot see a sign in the intersection. The 50 year old said he could see the sign, but he could not read it. The 13 year old said the sign says 16th street.


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## sanj (Mar 31, 2015)

My belief: Eye/brain combination is far more complex and flexible than a sensor. The moment the eye looks at a different object the brain adjusts the focus and brightness quickly. So this combination effectively gives much higher DR than Canon. (Perhaps not Sony). Hahahahahahah.


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## PropeNonComposMentis (Mar 31, 2015)

nc0b said:


> In respect to the DR of the eye, age is certainly a factor. A few years ago three of us were in a car: me in my 60s, a father in his 50s and his son age 13. I was looking for 16th street, and was stopped at a traffic light. I said I cannot see a sign in the intersection. The 50 year old said he could see the sign, but he could not read it. The 13 year old said the sign says 16th street.


With all due respect, that sounds like a genetic, or, traffic, aberration.
Age has nothing to with sight. The two leading factors that have the greatest influence on vision, are, food quality and quantity, and the correct lighting conditions.

I once knew a very nice fellow, 109yo. He would walk six miles into town for supplies, a six mile walk each way. He could see better than me. I watched him throw a stone and kill a rabbit for his supper a number of times.

So, what coloured eyes see the best ? And what coloured eyes come from a Recessive-Gene ?
A hint:- you will not find the answer on the Internet.


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## Maximilian (Mar 31, 2015)

PropeNonComposMentis said:


> nc0b said:
> 
> 
> > In respect to the DR of the eye, age is certainly a factor. A few years ago three of us were in a car: me in my 60s, a father in his 50s and his son age 13. I was looking for 16th street, and was stopped at a traffic light. I said I cannot see a sign in the intersection. The 50 year old said he could see the sign, but he could not read it. The 13 year old said the sign says 16th street.
> ...


With all due respect, too, cataract and glaucoma are more typical to old or to young people?
And can you tell me that just food or lighting conditions are reasons for those eye diseases?
And how about getting bad eyes because of extensive VDU work? Typical occupational disease these days.
Or is there possibly something like age?

Lucky one, your nice 109yo fellow. But I believe, he has good genes on one side and also "trained" his eyes well by using them almost in "prehistorical" conditions, outdoors and so on. Or did he also do VDU work?

I don't know anybody 70 years or older having better eyes than me.


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## zim (Mar 31, 2015)

PropeNonComposMentis said:


> nc0b said:
> 
> 
> > In respect to the DR of the eye, age is certainly a factor. A few years ago three of us were in a car: me in my 60s, a father in his 50s and his son age 13. I was looking for 16th street, and was stopped at a traffic light. I said I cannot see a sign in the intersection. The 50 year old said he could see the sign, but he could not read it. The 13 year old said the sign says 16th street.
> ...



That sounds like a geriatric abberation


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## StudentOfLight (Mar 31, 2015)

Here is a test you can do right in from of your monitor:
1) First, is your monitor is in a dimly lit room (as it should be)?
2) Place a dark object next to the monitor.
3) Open a web page which is predominantly bright.
4) Close one of your eyes.
5) Look at corner of the screen adjacent to the dark object.
6) Note whether or not you can you see see detail on the dark object and the bright screen at the same time?
7) Take a picture with the your DSLR by using the "Expose to the right" (ETTR) approach
8) look at the Image histogram. 

The Canon histogram shows 10 stops of dynamic range. If scene exceeds that then there will be a tall stack at the left edge of the histogram indicating details which would be lost in the shadows. If your eye could see those details then your eye has more instantaneous DR than 10stops.


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## privatebydesign (Mar 31, 2015)

PropeNonComposMentis said:


> So, what coloured eyes see the best ? And what coloured eyes come from a Recessive-Gene ?
> A hint:- you will not find the answer on the Internet.



It isn't strictly the eye colour that 'sees' best it is the brightness. But 'best' is subjective, are we talking better able to deal with high contrast 'best' or better able to discern colours 'best. If the former, darker eyes, typically brown would be best, if the latter lighter eyes, typically blue, would be better. 

The recessive gene for eye colour is easily found on the internet.


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## PropeNonComposMentis (Apr 1, 2015)

privatebydesign said:


> .....
> The recessive gene for eye colour is easily found on the internet.



No its not !

Your chart shows an ignorance of Genetics, as do a number of hasty assumptions above.

The Human Genome has been mapped, dont you know !


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## privatebydesign (Apr 1, 2015)

PropeNonComposMentis said:


> privatebydesign said:
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Your old persona was pretty annoying, this new one, where you claim greater knowledge and experience than everybody without actually imparting any of it whilst hinting at your vastly superior intellect is, boring. Goodbye.


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## PropeNonComposMentis (Apr 1, 2015)

privatebydesign said:


> PropeNonComposMentis said:
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Dont recall making any assertions regarding my intellect.

I know what I know. If I am wrong, prove it. I am more than happy to learn. But I will not stand quiet in the presence of indolent urban mythology being flogged as reality.


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## PropeNonComposMentis (Apr 1, 2015)

StudentOfLight said:


> Here is a test you can do right in *from* of your monitor:
> 1) First, is your monitor *is* in a dimly lit room (as it should be)?
> 2) Place a dark object next to the monitor.
> 3) Open a web page which is predominantly bright.
> ...



* I'll have what he's having ! *


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## PropeNonComposMentis (Apr 1, 2015)

Maximilian said:


> PropeNonComposMentis said:
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Hi Max.
Cataract and Glaucoma favor neither age nor sex.
can you tell me that just food or lighting conditions are reasons for those eye *diseases*?
Can you tell me the difference between Disease / Disorder / Sickness / Syndrome ? People use these words every day, anyone actually Know the difference ?

I ask my questions and challenge statements here in the hope that some of you will actually go away from here and find and learn for yourselves. Dont just take my word, or anyone's word as the only truth.

My 109yo friend was Asian. NO DISRESPECT Asian are know to be genetically predisposed to poor eye sight.
My friend was born, lived and worked his whole life, and died in 1980, on a small island with just two villages and a visiting floating market.
If any of you care to take a few moments and look into a book, you will find that all the Asian countries have invaded and occupied each other so very often and for many 1,000's of years.
It was he who told me about Asians and Sight issues, and continued on to say he had never learned to read or write because he could not see well enough.

He taught me a lifetime in the final ten weeks of his life. What a gracious gift.
How did such a man know and understand Genetics !

Sorry Max, no straight answers. Wish I knew more, to give you better answers.


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## Maximilian (Apr 1, 2015)

PropeNonComposMentis said:


> Hi Max.
> Cataract and Glaucoma favor neither age nor sex.
> can you tell me that just food or lighting conditions are reasons for those eye *diseases*?
> Can you tell me the difference between Disease / Disorder / Sickness / Syndrome ? People use these words every day, anyone actually Know the difference ?
> ...


Hello again, PropeNonComposMentis!

First of all please note that English is not my mother tongue. I am German, as you can read from my profile. 
Second, therefore I sometimes need to rely on dictionaries. And there is common uses of words, that can be understand right - normally. So please stop hairsplitting about words. And if anything about my post could be read as offensive please note that I didn't intend to. Especially about your 109yo friend. I really meant what I wrote there. 

Thirdly:


> I ask my questions and challenge statements here in the hope that some of you will actually go away from here and find and learn for yourselves.


I respect _(edit and really appreciate_ your intention here, as I sometimes also think people should learn for themselves. "RTFM" is one of my most beloved abbreviations. Of course I seldom use it because it's too offensive. But sometimes it is also justifiable to ask such a question as the OP did, because if an eye specialist can answer such a complex question within minutes you don't have to study the science of the eye or ophthalmology for several years.

Fourthly, back on topic:
It was YOU who stated 


> Age has nothing to with sight. The two leading factors that have the greatest influence on vision, are, food quality and quantity, and the correct lighting conditions.


without any further prove of this statement. And now it's YOU who says


> ...no straight answers.



I give you straight answers:
about Cataract (http://en.wikipedia.org/wiki/Cataract)
"_*Age *is the most common cause.[2] Lens proteins denature and *degrade over time*, and this process is accelerated by diseases such as diabetes mellitus and hypertension. Environmental factors, including toxins, radiation, and ultraviolet light, have cumulative effects, which are worsened by the loss of protective and restorative mechanisms *due to alterations in gene* expression and chemical processes within the eye.[10]_"

about Glaucoma: (http://en.wikipedia.org/wiki/Glaucoma)
"_Glaucoma affects one in 200 people aged 50 and younger, and *one in 10 over the age of 80*_" (so much about age)
"_*Women are three times more likely* than men to develop acute angle closure glaucoma due to their shallower anterior chambers_" (so much about sex)

Of course wikipedia.org is not a clinical study but the people posting there are referring on clinical studies.
Of course age is not THE factor but with *higher age* the factors add up. 
Of course not everybody gets a Cataract or Glaucoma but everybody's eyes are ageing like the rest of the body does as well. 
And that was the reason why I couldn't leave your original statement without comment. _(edit Otherwise I wouldn't have posted in this thread as I am not an eye specialist or did any deep research on this topic as well. But I was interested, if anybody could give a detailed answer_.
And Cataract and Glaucoma were just examples.
And by the way: you didn't say anything about extensive VDU (or computer desk, I looked it up) work.
I meant here reduced flexibility of focusing and adapting and the "Office Eye Syndrome".


Your turn.


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## Valvebounce (Apr 1, 2015)

Hi Maximilian. 
What is rude about Read The Flaming Manual? ;D ;D The way it is said? I used to regularly get "Don't talk to me in that tone of voice" from mother, I didn't know I had a tone of voice! :

Cheers, Graham. 




Maximilian said:


> I respect _(edit and really appreciate_ your intention here, as I sometimes also think people should learn for themselves. "RTFM" is one of my most beloved abbreviations. Of course I seldom use it because it's too offensive. But sometimes it is also justifiable to ask such a question as the OP did, because if an eye specialist can answer such a complex question within minutes you don't have to study the science of the eye or ophthalmology for several years.


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## Maximilian (Apr 1, 2015)

Valvebounce said:


> I didn't know I had a tone of voice! :


Sounds familiar to me :


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## noisejammer (Apr 1, 2015)

It's not difficult to put an upper limit on the eye's dynamic range. Occasionally, the moon will pass in front of the star Antares. If this happens near full moon, the brightness is well known (-12.74m) while Antares' brightness is +0.96m. The brightness difference is thus 13.7m which can be converted into linear units using 

Ratio = 2.512^13.7 = 302000. This in turn can be converted into bits using

DR(bits) = log(302000)/0.301 = 18.2bits.

The million dollar question is whether you can actually see Antares right up to the point where it is occluded by the moon. I've never been able to do this, so all I can say from this measurement is that my eye's dynamic range is definitively less than 18.2 bits when both images fall on the macula but it's quite easy to see both when they are separated by a moon diameter (nadits half a degree.)

A while back, I was contemplating the purchase of a 10-bit display. Since these are hideously expensive, I decided to test my eye's dynamic range on images. I created a test pattern with 1-bit increases in grey from an 8-bit input. Depending on the monitor, it was either impossible or marginal for me to discern a difference. This suggested that for an extended object, I could resolve 8 bits, 9 bits would be difficult and 10 bits was improbable. The 10-bit display stayed in the shop.

However, my observations of binary stars suggest a different answer. Antares - mentioned above - has a blue companion which shines at 5.5m. This represents a brightness difference of only 65.5x or 6 bits. The companion star has good contrast in colour and so _should be easily visible_ in small telescopes. In practice it is an extremely difficult, requiring good seeing, superior optics and high magnification. Since 8 bits corresponds to 6m and 10 bits to 7.5m, it seems that the angular size of the object plays a role.

A second anecdote from my youth. When I was 18, I was regularly able to observe two or three of the Galilean moons of Jupiter without a telescope. These are typically 6.5-7.5m ( 400-1000 times, 8.6-10 bits) dimmer yet they were comparatively easy.

The reason seems to be glare - most of which results from scatter within the eye itself. This glare is attributed to floaters (dead cells within the aqueous and vitreous humors) which accumulate with age. When an extended object is observed, scattering within the eye may average out.

Conclusion - when young, the true dynamic range was around 9 bits. Now scattering has reduced it to less than 6 bits and it may get worse. Contrary to assertions above, my vision has degraded measurably with age. As others have observed - growing old sucks.... but it's better than the alternative.


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## Marsu42 (Apr 1, 2015)

noisejammer said:


> This glare is attributed to floaters (dead cells within the aqueous and vitreous humors) which accumulate with age. When an extended object is observed, scattering within the eye may average out.



You're saying there are dead things floating around inside my eyes, and they're increasing!? Ugh, that's not what you want to read :-o



PropeNonComposMentis said:


> Asian *are know* to be genetically predisposed to poor eye sight.



Interesting, I'm seeing this study: http://www.asianscientist.com/2013/03/health/genetic-poor-eyesight-clearer-032013/

However, this is a recent study and I'd advise caution when basing conclusions on genetic factors. And who's an "Asian" anyway ... no so long ago people in my country tried to figure out who other "they" and "we" were, fortunately to no avail. Unless you do the reverse definition, i.e. people with poor eyesight have to be Asian 

Reminds me of the stereotypical Asian bad guy in Tintin comics, btw. This was in the time before they produced all the dslr equipment we're currently using :->


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## Maximilian (Apr 1, 2015)

Thank you, noisejammer, for your detailed thoughts. 

Your 


noisejammer said:


> Conclusion - when young, the true dynamic range was around 9 bits. Now scattering has reduced it to less than 6 bits and it may get worse. Contrary to assertions above, my vision has degraded measurably with age. As others have observed - growing old sucks.... but it's better than the alternative.


meets quite well with my gut instinct. So todays DSLRs deliver much more than you normally need, if you expose right 

I was really impressed about this


> When I was 18, I was regularly able to observe two or three of the Galilean moons of Jupiter without a telescope.


although I belive you, I must say it is hard to believe. 
I have had my own astronomical experiences in my youth. And I had good eyes, too. But I never had this experience like you had. Maybe the seeing wasn't good enough. But being on Elba in a really dark summer night should have worked.


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## dak723 (Apr 1, 2015)

IglooEater said:


> Cambridgeincolour puts the dynamic range of the human eye at around 10-14 stops. http://www.cambridgeincolour.com/tutorials/cameras-vs-human-eye.htm#sensitivity



10-14 is the answer they give for a theoretical situation where the eye's pupil does not change size. The estimated amount of DR for actual vision (in the same article) is estimated to be approx. 24 stops. This makes far more sense, as anyone who takes photos of a sunset notices that the camera falls far short in DR to capture both the highlights and shadows. So, sensors (even the Exmor) still fall far short of being able to come close to what the eye sees. That's one reason many of us just won't get that excited at the 2 stop difference in DR between Canon and Sony/Nikon.


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## noisejammer (Apr 2, 2015)

Maximilian said:


> .... I was really impressed about this
> 
> 
> > When I was 18, I was regularly able to observe two or three of the Galilean moons of Jupiter without a telescope.
> ...


Maximillian, I can offer better than anecdotes. A friend studies the ancient lore of San people. He has shown me evidence that they recognised Saturn as oval shaped and recorded it in carvings or rock paintings - I forget which. Even at their most open, the rings only subtend about 40x25 arcsec but the evidence is irrefutable and pre-dates the invention of the telescope.

I think that eyes degrade over the years but so does the brain's capacity to correct for aberration. This was particularly obvious to me as I wound my way through my academic career. I had refractive surgery to ease the burden about a decade back. After my eyes settled - this took perhaps a year or so - I found that the Galilean moons were again visible (but with difficulty). I have also claimed a naked eye observation of Venus' crescent (it's quite a large target but is difficult because of glare) and _think_ I've seen Saturn as an out of round point.

Of course, it's near impossible to convince the sceptical of this and being a frequent observer I know more or less what I expect to see. It can be hard to convince myself.


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## Maximilian (Apr 2, 2015)

noisejammer said:


> Maximillian, I can offer better than anecdotes. ...


The only really good anecdote about my eyesight is the following:
When I was about 23 my girlfriend at that time was looking for a new spectacles frame. She was shortsighted.
I was bored and stood around in the shop and remembering my last eye test back when I made my drivers license I looked at the test chart at the wall with all the letters on it. I asked the shop owner about the reading distance and he told me right there from where I was standing. 
Without cheating I asked him: "what about F, S, T, A, etc. and the small numbers reading 160% on the side of this line."
(don't know the original row of letters I could read back then)
He looked at me with a strange and puzzled look and then said: "Man, that would have been really good - if I had switched on the backlight of this chart. But now I believe I won't make much money with you." And smiled.


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