1Dx ISO100 high DR shadows SNR improvement

[tron]

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 ...)

 

[slowcarIX]

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?

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)

 

[weixing]

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

By the way, Panasonic had this feature built-in in some of their compact camera.

Have a nice day.

 

[rpt]

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?

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)

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.

 

[Neutral]

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

 

[Neutral]

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."

 

[Neutral]

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

 

[rpt]

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

You are right. The noise will be addressed for each pixel. It will be more noticeable in the shadows and darker areas of the image.

 

[Neutral]

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

 

[rpt]

Ok, I just tried it. Set it for 9 exposures. Set it on live view. After the first shot, I set the AF off and took the next 8. The noise reduction was significant. I shot decorative lights in the garden. The iso was 25600.
Yay!

Thanks Neutral

 

[rpt]

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

 

[tron]

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).

 

[PeterD]

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.

 

[Neutral]

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

 

[Neutral]

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.

 

[wickidwombat]

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

 

[Neutral]

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)

 

[Neutral]

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)))

 

[Neutral]

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.

 

[wickidwombat]

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)))

Lr enfuse doesn't make eye rending abominations like photomatix it takes the exposures and blends them so no noise gain anyway. I suspect in combination with your method it will enable some super clean files