Messages

16

EOS Bodies - For Stills / Re: 1Dx ISO100 high DR shadows SNR improvement

« on: November 16, 2012, 02:19:55 AM »

Just tried another with iso 100. I am happy. No NR needed in LR

One more happy user 
 That's nice and gives some good feeling to me 

17

EOS Bodies - For Stills / Re: 1Dx ISO100 high DR shadows SNR improvement

« on: November 15, 2012, 10:48:29 AM »

So I activate mirror lock just  before ME shot sequence  (done automatically after camera focused on the subject)  and then deactivate it after ME shot sequence  (using SET button - selectable option in mirror lock function) or it is deactivated itself later by camera itself .

Unfortunately this is not supported by my 5DMkIII that's why I was wondering how you can do that. So it's only Live View for me    (OK I know it is sufficient and actually a super set of Mirror Lock for this purpose but still ...)

  Actually mirror lock is not required – just an option to get better image sharpness – reducing camera vibrations and preventing refocusing for each ME shot in sequence.
If for first one nothing could be done with 5DM3 but for second one it is possible to focus automatically then switch lens to manual focus to keep focus unchanged during  ME sequence

18

EOS Bodies - For Stills / Re: 1Dx ISO100 high DR shadows SNR improvement

« on: November 15, 2012, 10:36:51 AM »

  As I understand it, the pixel data will be averaged and not summed as that is what is selected in step 1.3. So my understanding is that the exposure should be sufficient to capture all the light for the subject. It is only in the dark areas that the random noise will be evened out.

Neutral, do correct me if I did not get it right.

Averaging is summing up all the values and then dividing result by number of samples.
Mathematically averaging is (A1+A2+A3 +...+AN)/N where N is number of samples.
  By using ME method Image SNR will be increased for every pixel on the image - regardless if this shadows or highlights where SNR is already high and will be even better.
As result of cleaner image you can use more aggressive sharpening without any visible problems on the image

19

EOS Bodies - For Stills / Re: 1Dx ISO100 high DR shadows SNR improvement

« on: November 15, 2012, 10:33:41 AM »

Thank you!
Will single long exposure achieve the same effect keeping iso constant?
9 exposure with total integration of 2.5secs = smaller aperture and keeping shutter open for 2.5secs?

Unfortunately this will not help.
 Basically by doing so you will be just reducing amount of light per time unit to the sensor to keep exposure longer  to obtain the same amount of light. 
    Mutli-Exposure  method is different  - it allows to capture more light - up 9 times more for 1Dx (and 10 times more for  Nikon D800) than in single shot and then averaging that  (normalizing)  to one single shot image . But random noise is not increased by 9 times but only  by  Sqrt(9)=3
 So after averaging 9 shots in ME sequence  (normalizing it to one shot) we will have  10*log(9/sqrt(9))=10*log(3)= 4.7dB  image SNR improvements.

 On the link below you can find detailed explanations - I was referring this in one of my previous post .
Found it when was searching for something that could answer all the questions.
http://www.cambridgeincolour.com/tutorials/image-averaging-noise.htm
 " In general, magnitude of noise<http://www.cambridgeincolour.com/tutorials/image-noise.htm> fluctuation drops by the square root of the number of images averaged, so you need to average 4 images in order to cut the magnitude in half."

20

EOS Bodies - For Stills / Re: 1Dx ISO100 high DR shadows SNR improvement

« on: November 15, 2012, 10:30:07 AM »

    This method is commonly use in Astrophotography to reduce noise (mainly to reduce random noise) and improve image quality...

This correct. And they could use thousands and thousands of images for averaging to extract details that far below noise level.   And have supercomputers to do this using sophisticated processing algorithms – not just simple averaging

21

EOS Bodies - For Stills / Re: 1Dx ISO100 high DR shadows SNR improvement

« on: November 14, 2012, 10:35:19 AM »

For me  to make it easy to use  I just registered ME  and Mirror lockup in the1Dx  custom menu (last tab).

Neutral: could you please give a step by step instruction how this can be done?

Thanks!!

This is how to  do this in 1Dx:
1.      Enable multi-exposure
1.1. Set ME mode to continuous .
1.2.  Set number of exposures to 9  (or any between 4 an 9 - smaller number will give less SNR improvement)
1.3.  Set multi-exposure control to  Average (to integrate over 9 images) ,
2.      (Optional) Switch on  mirror lock up function with the SET button deactivation to reduce camera vibration (will be deactivated  by SET button).  See explanation for this in my post above

3.      Switch on Long exposure NR - set it to auto - will be used for shots longer than 1 sec or set it ON -"forced" .  This adds additional SNR improvements and significantly reduce banding

4.      Put camera in high speed continuous shooting mode  ( optional - if you are shooting in high DR daylight environment to make ME shot very fast) ,  press shutter - mirror will be locked, press shutter again  to start ME shot  and keep it  pressed for each next shot in ME sequence until ME sequence is completed
 Camera will take quickly 9 images in less than 1 sec (that for daylight - at night will be longer ), stops and then merge it ( integrate)  into one image.
And you are done.
Now press set button to return mirror back (if mirror lock was used)  and then you could see the result.
Method is suitable for only still images.
In normal (daylight) conditions such kind of shot will take about 0.75 sec with FPS =12
And of course method should be used with strong stable tripod for camera and remote shutter control (to prevent image blurring due to camera vibrations and get highest possible resolution)

22

EOS Bodies - For Stills / Re: 1Dx ISO100 high DR shadows SNR improvement

« on: November 14, 2012, 10:31:52 AM »

Just  a question. You mentioned that you kept the mirror locked until the end of the sequence. Do you mean that the mirror was up the whole time ?Assuming that 5D3 and 1Dx are exactly the same in ME this cannot happen unless you are using LiveView. Unless you meant you had activated mirror locking and you deactivated it afterwards. But in that case the mirror moves up before and then down after every shot.

  Actually  I was activating mirror lock before ME sequence and then deactivating it afterwards - this was more convenient for me. To keep it up until sequence is completed it should be set to be released by set button instead of deactivating after each shot.
But I think live view mode also could be used for that.
Here is some more explanations for Mirror Lock:
As a matter of fact use of mirror lock for ME shot is not required but very desirable.
  My main goal was not only to improve 1DX SNR performance in high DR environment but also to get maximum possible image quality regarding sharpness and clarity - actually to squeeze whatever possible from 1Dx regarding IQ.
  So I activate mirror lock just  before ME shot sequence  (done automatically after camera focused on the subject)  and then deactivate it after ME shot sequence  (using SET button - selectable option in mirror lock function) or it is deactivated itself later by camera itself .
Below is the outcome of using Mirror Lock
1.      This reduces camera vibrations thus contributing to best image sharpness -nothing new in that.
2.      The other result of using mirror lock is that camera focuses once before ME sequence and does not try to refocus for each shot in ME sequence thus preventing losing sharpness as result that for each ME shot focus could be slightly different.  This is equivalent that you set manual focus for all sequence in ME shot.
  Of course if image sharpness is not required and only shadows SNR is the concern ( e.g. for small print) then ME shot could be done without Mirror Lock.

23

EOS Bodies - For Stills / Re: 1Dx ISO100 high DR shadows SNR improvement

« on: November 14, 2012, 10:28:28 AM »

Glad if that was useful to any of 1Dx users.

I guess you helped 5DMkIII users too as the Multiple exposure capabilities of the two cameras seem similar 
So thank you on behalf of the 5DMkIII users too ...

My pleasure again)))
At some point it is more pleasure to give people something useful for them rather then  get something for himself)))
There is also very interesting side-effect of this ME method.
Probably someone has already noticed that in the real life examples posted above.
This side effect is also extremely useful.
Because image is so clean (extremely low noise level) this allows applying significantly more aggressive sharpening to the image without any noticeable problems.
Just on two last examples above - with no noise reduction in LR sharpness slider is set to 40 and details to 100.
Single shot is practically unusable for big prints
And second ME shot is still clean and full of details (see the curtains in the left window).
With just small amount of NR applied (about 10 -15) and using properly set sharpen mask slider it is possible to move safely sharpness slider up  to 50-60  (also reducing radius  below 1 ) and get perfect per pixel sharpness  which is practically impossible using single shot in such high DR low light environment.

24

EOS Bodies - For Stills / Re: 1Dx ISO100 high DR shadows SNR improvement

« on: November 13, 2012, 01:30:00 PM »

Tried this trick out tonight and it works a treat!

I never noticed how much noise was in the shadows at 100 ISO before. This method really helps bring out the details.

Thanks for sharing, I can't wait to use this more.

My pleasure)))
Glad if that was useful to any of 1Dx users.
It would be nice if Canon could put that in firmware upgrade as single button press feature.
This is very simple to implement.
For me  to make it easy to use  I just registered ME  and Mirror lockup in the1Dx  custom menu (last tab).

And now one more real life comparison of 1DX single shot and ME shot using method described above.
  Two 200% crop with no noise reduction in LR showing how clean 1Dx  ISO100 ME shot  compared to the single shot.
 And also 1Dx ME shooting mode  performance shown on DxoMark  SNR measurement curves  with comparison to Nikon D800 and D4 single shot. (I do not know if they have the same ME shooting mode).
Hope that seeing all that could make many 1DX users more happier about the camera)))

25

EOS Bodies - For Stills / Re: 1Dx ISO100 high DR shadows SNR improvement

« on: November 12, 2012, 09:45:43 AM »

 Was checking  latest updates for new Sony DSC-RX1 which is expected mid december and found something very interesting.
Sony DCS-RX1  will be using the same ME noise averaging method  described above for two stops SNR improvement.

  Clever Sony engineers – they use whatever possible and available (both TECHNOLOGY and METHODS) to improve SNR performance and grabbing ideas directly from the air and putting all that in camera as standard features.
Seems that Sony DCS-RX1 could be very nice walk around camera...
---------------------- 
http://www.bhphotovideo.com/c/product/891105-REG/Sony_dscrx1_DSC_RX1_Full_Frame_Point.html/c/product/#inpage:IN+STOCK

“Low-light Performance
  The maximum selectable ISO setting is 25600, which enables low-light shooting without a flash. In addition, DSC-RX1 can capture six images in a fraction of a second and combine the data from all six to create a single image with a reduction in noise equivalent to two additional steps of ISO sensitivity.”

26

EOS Bodies - For Stills / Re: 1Dx ISO100 high DR shadows SNR improvement

« on: November 11, 2012, 01:27:49 PM »

One more example of 1Dx ISO100  ME shot in action.
From series  “Another world dimensions “   -  through reflections in water.
Small snapshot from LR screen is shows level of noise

27

EOS Bodies - For Stills / Re: 1Dx ISO100 high DR shadows SNR improvement

« on: November 10, 2012, 11:56:10 AM »

Thanks, Neutral. Nice shot, and definitely improved by the post processing.

  And all that became possible (to have noise free shadows with all details) as result of SNR improvement using ME shot.  Basically there was a very little bit of post processing for that in LR.
Just few basic things.
  Using method described above it is possible to improve 1Dx low ISO SNR by 4.7db plus what is added by long exposure NR  ( I believe that s about 10*Log(SQRT(3)=1.5 dB.
So in total about 6 db SNR improvement directly from the camera single RAW file  without any post processing for strong NR and all that allow easily recover of shadows without need to spend time on  HDR.
I can post couple of more real life shots using this method a bit later – demonstrating the same virtually noise free recovered shadows.   Just single short HDR imagedirectly  out of camera – just pull down highlights and raise shadow in LR – this is  all what is required

28

EOS Bodies - For Stills / Re: 1Dx ISO100 high DR shadows SNR improvement

« on: November 10, 2012, 08:38:20 AM »

  So far in this thread I was describing concept how 1DX performance could be significantly improved for low light high DR shots shadows at ISO100   - with some stress test shots showing to what extent (strength) this is applicable in real life and what SNR improvement we can get out of that   - just with a single output RAW file directly from the camera without no post processing we have additional 4.7dB of SNR improvement
OK, now to the final part of the subject – how all that works in real life combined together with long exposure NR that is applied by camera to every shot merged in final ME shot. I believe that that long exp NR is done by subtraction of calibration shot with shutter closed from the next normal shot thus eliminating banding patterns.

So now here is a real life example.

1. First shot is AS IS from the camera - properly exposed multi-exposure shot with -0.7EV shift to allow highlights to be recovered. Exposure shift was selected after few test shots to see what is the best EV
   But this is not what I see in reality and does not convey mood and feeling of what I see in real life.
Shot is dark, flat, no feeling of space and distance –as nothing seen on the foreground, reflections in the water not seen well – as water is a bit rough.  Shot just allows recognizing the place – no more than that.
-----------
2. Second image is original ME shot  which is processed to my feelings and of course a bit exaggerated to be a little bit more catchy.
   All was done within LR.   Local brush was used to raise EV and shadow in the foreground so something could be seen close to the camera to give feeling of distance and space and be close as I was seeing that.  The same for the sea surface to bring it from the dark.
Both above  are exported from LR4  as 800px sRGB  100% jpeg with preserved camera EXIF data so that anyone could check that these images are really from 1Dx and not from the medium format camera.
And now is most interesting part - two 200% crop snapshots from the LR screen using Win7 snip tool) to show image quality.
-------------
3.   200% scale  crop of the far city towers .  Please note absolute lack of noise in the sky – it is absolutely clean, transparent and it has natural “liquid” look.
Note that noise in shadows is also  not visible  but fine details are clean and clear. You even could notice two ropes between two towers – from the top of the blue tower going diagonally down towards white/yellow tower on the left.
 And this is from the distance of about 3km away from those towers!!!
 This is image quality which is close to the IQ that could be observed on medium format cameras.
For sharpness there are also several additional factors which are playing significant role in reaching such IQ in low light high DR environment:
- mirror is locked for all duration of multi- exposure sequence – released manually after completing the  last ME shot
 - amazing  sharpness and  micro-contrast of the new 24-70 F/2,8L II USM lens – my piece is just like unbelievable miracle  - I will post something related to that on 1DX body  in new thread some time later.
- averaging of 9 ME shots each is  2.5 sec  and few seconds interval between each ME shot  results  in almost 1 min total exposure and this effectively  filters out atmospheric  turbulence  which could be noticeable on single shot image for such distance.
--------------
4. Final is 200% of the crop of the foreground grass raised from absolute darkness.
   Note that there are no traces of any noise and banding here at all.
   This is not in lens focus – the same as I see it when look at far distance. 
    Foreground was raised from shadows to the level to be able to see something close in order to give feeling of the distance and space.

29

EOS Bodies - For Stills / Re: 1Dx ISO100 high DR shadows SNR improvement

« 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 )))

30

EOS Bodies - For Stills / Re: 1Dx ISO100 high DR shadows SNR improvement

« 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.