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Messages - Neutral

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31
HDR - High Dynamic Range / Re: Problems with Noise in Dark Areas
« on: November 16, 2012, 06:08:05 AM »
....
  HDR is as much an art as any other technique.  Use it, don't abuse it.
Exactly, frequently we see just opposite  :(

32
EOS Bodies - For Stills / Re: 1Dx ISO100 high DR shadows SNR improvement
« on: November 16, 2012, 03:35:59 AM »
Neutral - thanks for the in-depth explanation - I'm anxious to try out your ME method...
As a matter of fact this is not my method  :)

This technique  was being used around for decades in different areas.

  I just was not very happy with 1Dx low ISO SNR performance  (as I like night/evening shooting)  and when saw that ME function in 1Dx – my first thought was that this could be workaround until we get new rumored Hi-Res camera that should bring some new sensor technologies.  I was tempting to buy Nikon D800 but thought that I can wait and do something with 1Dx.   

 Actually Multi-Exposure term is coming from old film times when in order  to mix together several  images you had to do multiple exposure from different frames on the same piece of photo paper.
Same functionality was main goal of introducing ME in digital cameras – and one of the application of this to catch phases of object movement in one shot - but there are also many other interesting artistic applications for that

Noise averaging using ME for improving SNR is just very useful side effect of this functionality.

And the other side effect which is also very useful -  is to simulate ND filter for long exposure.
Using ME method one will be getting much cleaner images than using ND filter to reduce amount of light into camera sensor.
If both are combined together (ND filter and ME method) you can get very interesting artistic effects due to ability to have very long exposures at day time.  I did not tried that yet but going to do so at some time.

33
EOS Bodies - For Stills / Re: 1Dx ISO100 high DR shadows SNR improvement
« on: November 16, 2012, 02:39:39 AM »
Neutral have you tried mixing this with other HDR techniques? say -2EV and +2EV then using enfuse to blend
so a total of 27 shots? 3 combined super clean files blended together I think there is lots of potential with adapting this technique. Thanks for the find I cant wait to give it a go
I did not try that  but I think this could be very interesting.
Known issue for HDR is increasing image noise.
So having virtually noise free images from camera using ME could help get cleaner and better HDR images. When I look at some HDR images posted around I frequently want to take wet tissue and wipe that noise away as this is causing pain for my eyes)))

34
EOS Bodies - For Stills / Re: 1Dx ISO100 high DR shadows SNR improvement
« on: November 16, 2012, 02:32:56 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
Mirror lock is required for sharpness. There is no point in trying to lower the noise merely to induce camera shake. But is is achieved with LiveView. Anyway for shots on tripod - when it is getting dark - I use Mirror Lock and 2 second delay. Focusing is either AF and then turned to manual or Live View (with manual focus and 10x). So the only additional function is the Multiple Exposure (Mirror is Locked in LV).
I could not imagine that 5DM3 does not have similar as 1Dx option to keep mirror locked up for 30 seconds with early deactivation by SET button.
That’s good that you found a way for 5DM3 to keep mirror locked during ME sequence.
With that 5DM3 could have an edge over 1Dx for such kind of ME night/evening shots due to better sensor resolution.
   The only one thing I do not understand why Canon did not  do that as F/W feature with single button press as done in some other cameras (e.g. upcoming Sony DCS-RX1).  This is so simple to add that in F/W to give user easy way to cope with deep shadow noise issues at ISO100 for 1Dx and 5DM3.  They know the problem they know (I hope) how to deal with that so why not to make life easier to camera users who like night/evening shooting.
  It would be also interesting to see outcome of this noise averaging method on Nikon D800.
D800 could have up to 10 shots in ME sequence.  Combined with camera 36mpx sensor resolution and high DR outcome using this method could be really amazing (with good Hi-Res lens)

35
EOS Bodies - For Stills / Re: 1Dx ISO100 high DR shadows SNR improvement
« on: November 16, 2012, 02:30:00 AM »
Neutral - thanks for the in-depth explanation - I'm anxious to try out your ME method.

BTW - my 1DX is my first 1 series camera - I'm loving it but there is a learning - it's threads like yours that I find helpful - inspired me to register at canonrumors. Thanks again. :)
Thanks for good words :)
My pleasure ))
 This is just illustration to what I was telling several times in some other posts – instead of useless arguments over subject(s)  that some most involved have no ideas or knowledge – better do something useful for others if you can do that )))
  And this was the reason I join forum recently – I got very tired of reading all that heated disputes about DXO sensor measurements  between people who do not understand that at all and wanted to show how  simple MATH is applied to real life.

36
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  :)

37
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

38
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

39
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."

40
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

41
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)

42
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.

43
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  ;D
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.

44
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)))

45
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.”

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