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Author Topic: 1Dx ISO100 high DR shadows SNR improvement  (Read 13188 times)

Neutral

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Re: 1Dx ISO100 high DR shadows SNR improvement
« Reply #30 on: November 06, 2012, 12:51:41 PM »
If you nail your exposures on either camera, only good photos will result.

.....but why would you do this when it's so much fun to intentionally underexpose an image by 5 stops then crank on the sliders in Lightroom. Yeeehawww, keep pushing those sliders over to the right!

Good times :)

  That all above is  not about the fun of making underexposed shots and pulling them up but about  normal 0EV shots for high DR scenes  and where it is desired  to see details in deep shadows instead of noise or instead of totally black areas.   And how to push 1Dx limits in this area.
   If one is trying to make fun of something  and this one does not fully realize what is the whole subject about  then yes  this making people to smile but not about the joke itself  but rather about the person who tried to make such joke))
Have fun  )))

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Re: 1Dx ISO100 high DR shadows SNR improvement
« Reply #30 on: November 06, 2012, 12:51:41 PM »

RLPhoto

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Re: 1Dx ISO100 high DR shadows SNR improvement
« Reply #31 on: November 06, 2012, 12:53:55 PM »
If you nail your exposures on either camera, only good photos will result.

.....but why would you do this when it's so much fun to intentionally underexpose an image by 5 stops then crank on the sliders in Lightroom. Yeeehawww, keep pushing those sliders over to the right!

Good times :)

  That all above is  not about the fun of making underexposed shots and pulling them up but about  normal 0EV shots for high DR scenes  and where it is desired  to see details in deep shadows instead of noise or instead of totally black areas.   And how to push 1Dx limits in this area.
   If one is trying to make fun of something  and this one does not fully realize what is the whole subject about  then yes  this making people to smile but not about the joke itself  but rather about the person who tried to make such joke))
Have fun  )))

I love quotes taken out of context.   ::)
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Re: 1Dx ISO100 high DR shadows SNR improvement
« Reply #32 on: November 06, 2012, 01:20:56 PM »
To improve results it would  required to do calibration shot just before shooting session - similar what is done with Gray/wite/black card before session for later WB adjustement
It is not quite constant. I did some experiments merging hundreds of images (don't ask), and the areas where banding seems to occur are clustered but not constant (over periods of a few hours).

However, if your exposure is more than 1s, turn on long exposure noise reduction. On my 5DIII at least, this removes most of the banding. The downside is that the general noise level rises (which also helps hide the banding), so you will need to average several such frames to get the noise back down again.

Another thing that seems to work well with multi-exposures is for images that need contrast stretching. For example, if you have an image with very low contrast (fog), combining multiple frames (eg in PS) can give you more latitude for  contrast adjustment.

In general though, if shadow noise is a problem, you are better off shooting multiple exposures, as for HDR. With a three-shot bracket, you can extend the usable dynamic range by six stops. To do the same by averaging frames you would need an awful lot more - and if the pattern noise is correlated the result will be worse.

nightbreath

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Re: 1Dx ISO100 high DR shadows SNR improvement
« Reply #33 on: November 06, 2012, 03:03:17 PM »
So as you suggested I did noise comparison for original RAW and  TIFF (lossless converted from RAW, to16 bit TIFF, color space is the same Adobe RGB, no re-sampling - the same pixel count).
Quick question. Did you create TIFF image via DPP as opposed by this method?
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V8Beast

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Re: 1Dx ISO100 high DR shadows SNR improvement
« Reply #34 on: November 06, 2012, 03:08:53 PM »
If you nail your exposures on either camera, only good photos will result.

.....but why would you do this when it's so much fun to intentionally underexpose an image by 5 stops then crank on the sliders in Lightroom. Yeeehawww, keep pushing those sliders over to the right!

Good times :)

  That all above is  not about the fun of making underexposed shots and pulling them up but about  normal 0EV shots for high DR scenes  and where it is desired  to see details in deep shadows instead of noise or instead of totally black areas.   And how to push 1Dx limits in this area.
   If one is trying to make fun of something  and this one does not fully realize what is the whole subject about  then yes  this making people to smile but not about the joke itself  but rather about the person who tried to make such joke))
Have fun  )))

The joke is that you can't figure out that I quoted RL Photo, not you. Therefore, my response was directed at RL Photo's, not yours.

For future reference, when a post reads "Quote from: RL Photo," unless your user name is RL Photo, the comments in it aren't something for you to get overly defensive about. Failing to understand something this simple is funny, and I didn't even have to make a joke about it :) Thanks for making my job easier :)


« Last Edit: November 06, 2012, 03:10:56 PM by V8Beast »

arcanej

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Re: 1Dx ISO100 high DR shadows SNR improvement
« Reply #35 on: November 06, 2012, 05:13:14 PM »
After the election today, can we have a four year moratorium on posts extolling or dumping-on a camera based on pictures that are 3+ stops underexposed?

sandymandy

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Re: 1Dx ISO100 high DR shadows SNR improvement
« Reply #36 on: November 07, 2012, 09:25:03 AM »
evening/night  city shots


Who is gonna do low light shots with ISO 100? Seriously? TBH i think people with an 1DX ususally dont f___ up their photos so badly like -3EV by accident.

@ "cap on lens photography"

check this guy:

How to NOT use a Leica Small | Large


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Re: 1Dx ISO100 high DR shadows SNR improvement
« Reply #36 on: November 07, 2012, 09:25:03 AM »

neuroanatomist

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Re: 1Dx ISO100 high DR shadows SNR improvement
« Reply #37 on: November 07, 2012, 09:32:50 AM »
evening/night  city shots

Who is gonna do low light shots with ISO 100? Seriously?


Mad dogs and Norsemen?   ::)

Oh, and me...


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Neutral

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Re: 1Dx ISO100 high DR shadows SNR improvement
« Reply #38 on: November 07, 2012, 11:40:31 AM »
To improve results it would  required to do calibration shot just before shooting session - similar what is done with Gray/wite/black card before session for later WB adjustement
It is not quite constant. I did some experiments merging hundreds of images (don't ask), and the areas where banding seems to occur are clustered but not constant (over periods of a few hours).

However, if your exposure is more than 1s, turn on long exposure noise reduction. On my 5DIII at least, this removes most of the banding. The downside is that the general noise level rises (which also helps hide the banding), so you will need to average several such frames to get the noise back down again.

Another thing that seems to work well with multi-exposures is for images that need contrast stretching. For example, if you have an image with very low contrast (fog), combining multiple frames (eg in PS) can give you more latitude for  contrast adjustment.

In general though, if shadow noise is a problem, you are better off shooting multiple exposures, as for HDR. With a three-shot bracket, you can extend the usable dynamic range by six stops. To do the same by averaging frames you would need an awful lot more - and if the pattern noise is correlated the result will be worse.
Thanks, interesting info about banding.
Also I agree, one could use HDR to increase DR.
And I was using that occasionally (in Photomatix or PS) but did not like that much for reasons listed below.
Of course if 1Dx could do in-camera HDR similar to 5DMIII than this would be very nice.
One of the problems with HDR is that this requires careful post-processing which is time consuming.
And “time is money” – very valuable thing.
 Also known problem with HDR is that though it allows to increase image DR significantly it also increases image noise which becomes more visible.  So one of the practices for HDR is to do NR on each image before merging them into final HDR. This also additional time in post processing
 My goal was to try to get out of 1Dx cleanest image that practically does not require any post processing .    Almost 2 stops SNR improvement for shadow areas (actually 4.7 dB)  is sufficient for many if not most of  high DR evening/night shots.   And all that with just one button press ( or two if you want to have mirror lock to reduce camera vibrations to get best possible resolution).
  And if a little bit of NR applied then you can get very clean image with good details and low noise level  in deep shadows.   
  As for long exposure noise reduction – sure - this is very useful feature. 
I do not know how Canon implementing this but in my first digital camera (Sony DSC-828) it was done by subtracting pure noise shot ( sensor read with shutter closed ) from image done after that.
And that was working very well.
« Last Edit: November 07, 2012, 11:54:36 AM by Neutral »

Neutral

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Re: 1Dx ISO100 high DR shadows SNR improvement
« Reply #39 on: November 07, 2012, 11:52:22 AM »
So as you suggested I did noise comparison for original RAW and  TIFF (lossless converted from RAW, to16 bit TIFF, color space is the same Adobe RGB, no re-sampling - the same pixel count).
Quick question. Did you create TIFF image via DPP as opposed by this method?
No DPP,  just lossless TIFF export from LR.
   I removed DPP from my PC long long time back as what I have (LR, DXO Optic Pro and Phase One Capture One)  together give me all functionality and quality I need. Use one of them which is better suited for what I want to do at the moment - but with latest LR improvement use other two less and less/
Mathematically any lossless conversion from RAW to TIFF should not change any image metrics – this is why it called lossless.  If it changes something then it is not lossless – it either changing something or distort something. Change in noise level only possible if high special frequencies are suppressed – e.g. with down sampling which introduce some image info losses.
I can try to export RAW to TIFF in C1 but 100% sure will have the same result.
So I do not believe that converting RAW to TIFF does any image SNR improvements –just from pure math angle of view.

Neutral

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Re: 1Dx ISO100 high DR shadows SNR improvement
« Reply #40 on: November 07, 2012, 11:58:50 AM »
evening/night  city shots
Who is gonna do low light shots with ISO 100? Seriously?

Mad dogs and Norsemen?   ::)

Oh, and me...

Nice pictures by the way.
Evening/night shots always carry on some special mood and feeling.
Also it seems that you have set of all the best lenses from Canon including TS ))))
Was always thinking of getting TS lens )))

tron

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Re: 1Dx ISO100 high DR shadows SNR improvement
« Reply #41 on: November 07, 2012, 12:25:40 PM »
Who is gonna do low light shots with ISO 100? Seriously?
Eh, hmmm, there is an accessory called tripod that facilitates this ::)

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Re: 1Dx ISO100 high DR shadows SNR improvement
« Reply #42 on: November 07, 2012, 12:42:48 PM »
Eh, hmmm, there is an accessory called tripod that facilitates this ::)

FWIW, that 35L shot above with the 2.5 s exposure was 'assisted' handheld, resting the camera on a bridge railing.   :D
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Re: 1Dx ISO100 high DR shadows SNR improvement
« Reply #42 on: November 07, 2012, 12:42:48 PM »

tron

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Re: 1Dx ISO100 high DR shadows SNR improvement
« Reply #43 on: November 07, 2012, 12:46:58 PM »
Eh, hmmm, there is an accessory called tripod that facilitates this ::)

FWIW, that 35L shot above with the 2.5 s exposure was 'assisted' handheld, resting the camera on a bridge railing.   :D
I do remember this from another thread of yours  :)

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Re: 1Dx ISO100 high DR shadows SNR improvement
« Reply #44 on: November 07, 2012, 01:35:23 PM »
So as you suggested I did noise comparison for original RAW and  TIFF (lossless converted from RAW, to16 bit TIFF, color space is the same Adobe RGB, no re-sampling - the same pixel count).
Quick question. Did you create TIFF image via DPP as opposed by this method?
No DPP,  just lossless TIFF export from LR.
   I removed DPP from my PC long long time back as what I have (LR, DXO Optic Pro and Phase One Capture One)  together give me all functionality and quality I need. Use one of them which is better suited for what I want to do at the moment - but with latest LR improvement use other two less and less/
Mathematically any lossless conversion from RAW to TIFF should not change any image metrics – this is why it called lossless.  If it changes something then it is not lossless – it either changing something or distort something. Change in noise level only possible if high special frequencies are suppressed – e.g. with down sampling which introduce some image info losses.
I can try to export RAW to TIFF in C1 but 100% sure will have the same result.
So I do not believe that converting RAW to TIFF does any image SNR improvements –just from pure math angle of view.
Canon software might be dealing with RAW image even better than the method you suggested. Just wanted to check  :)
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Re: 1Dx ISO100 high DR shadows SNR improvement
« Reply #44 on: November 07, 2012, 01:35:23 PM »