Question regarding ISO 50 on 5D III

[picture-this]

I realize that ISO 50 is not a native setting on the new 5D III camera.
My understanding in general terms is that ISO 50 has less grain and more color saturation compared to ISO 100 to begin with, especially with print film.
My question is due to the ISO 50 setting being NOT NATIVE, will actual photo prints of 11"x14" or larger show more noise/ image degradation versus the NATIVE ISO 100 setting?
I don't have a current digital camera that enables this option to compare for myself.
I would appreciate any thoughts or explanations from anyone willing to share for myself and others reading this forum!

[neuroanatomist]

No extra noise, but since it's 'pulled' you effectively lose a stop of highlights.

[JoeDavid]

Maybe just an odd occurance but, from the RAW files posted at the link below, I found the ISO 50 image to have less noise in the shadows than ISO 100:

http://www.imaging-resource.com/PRODS/canon-5d-mkiii/canon-5d-mkiiiTHMB.HTM

I used the Beta ACR converted with the noise reduction turned off and looked at all of the ISOs from 50 to 25600.  The shadows definitely exhibit less color noise in the ISO 50 shadows (most noticable between the Crayola crayon box and the pepper oil bottle just below the fabrics).  Canon may be doing some "on chip" noise reduction before the RAW file creation and it functions at ISO 50 as well resulting in less noise.  I don't think I've seen anyone else comment on it but ISO 50 definitely has less noise if you turn off all of the software noise reduciton when processing the files to compare them...

[briansquibb]

Maybe just an odd occurance but, from the RAW files posted at the link below, I found the ISO 50 image to have less noise in the shadows than ISO 100:

http://www.imaging-resource.com/PRODS/canon-5d-mkiii/canon-5d-mkiiiTHMB.HTM

I used the Beta ACR converted with the noise reduction turned off and looked at all of the ISOs from 50 to 25600.  The shadows definitely exhibit less color noise in the ISO 50 shadows (most noticable between the Crayola crayon box and the pepper oil bottle just below the fabrics).  Canon may be doing some "on chip" noise reduction before the RAW file creation and it functions at ISO 50 as well resulting in less noise.  I don't think I've seen anyone else comment on it but ISO 50 definitely has less noise if you turn off all of the software noise reduciton when processing the files to compare them...

With my 5d2 I felt the image better at iso50 too which I posted a couple of days ago.

DxO also measured better numbers at iso50 for both 1Ds3 and 5D2 - add in the 7D for the comparison  -  interesting figures

[picture-this]

Great stuff, thanks.
If we're talking about jpegs direct from the camera, can we throw the improvements between ISO 50 to 100 out the window?

[JoeDavid]

Great stuff, thanks.
If we're talking about jpegs direct from the camera, can we throw the improvements between ISO 50 to 100 out the window?

From looking at the noise in the various ISOs from the RAW files with no noise reduction during ACR processing, I doubt you'll tell any difference between them.  It wasn't a huge difference between 50 and 100 but it was clearly visible at 100% (pixel peeping...).  In fact, in JPEGs directly from the camera, I doubt you'll tell much of a difference from ISO 50 to 400!  800 looked like it will clean up with minimal loss of detail too.  Above that, the noise level starts to ratchet up signficantly with each full ISO step.  I will say though that the noise remained in a "tight" pattern all the way up through 12800; it just gets heavier as you go up but maintains quite a bit of detail.  At 25600 you start to see some of the random large chucks of noise that really impacts small details in the image and I wouldn't even bother with H1 or H2 unless you're desperate for any image at all.

Remember these comments are based on the Imaging Resources RAW files shot with studio lights.  To me they represent near "ideal" conditions.  Out in the real world, any underexposing of images always results in greater noise...

[nvsravank]

I understand why the high ISP are effectively enabled via custom settings. What is the reason for the Low ISO to have this custom setting security? 
What do we lose from ISO 100 by going to ISO 50?
If it is dynamic range, does it seem that the photos are actually more punchier due to the higher contrast?

[awinphoto]

In film, you are correct, but in digital, until they make it an actual default setting and not an expanded setting, you will not see any less noise, but you may see more room for highlight recovery in post production.  It would be nice if Canon/nikon really developed this ISO to match the saturation and buttery smoothness of the old velvia films and the like... as of now, it's good if you need to have longer exposures (running water scenes for instance) but not much anything else. 

[briansquibb]

In film, you are correct, but in digital, until they make it an actual default setting and not an expanded setting, you will not see any less noise, but you may see more room for highlight recovery in post production.  It would be nice if Canon/nikon really developed this ISO to match the saturation and buttery smoothness of the old velvia films and the like... as of now, it's good if you need to have longer exposures (running water scenes for instance) but not much anything else.

It is also useful for keeping the DOF narrow ie moving from f4 to f2.8 just by chnging the iso from 100 to 50

I am taking some portraits tomorrow - I will take them at iso50 to see if they are better

[awinphoto]

In film, you are correct, but in digital, until they make it an actual default setting and not an expanded setting, you will not see any less noise, but you may see more room for highlight recovery in post production.  It would be nice if Canon/nikon really developed this ISO to match the saturation and buttery smoothness of the old velvia films and the like... as of now, it's good if you need to have longer exposures (running water scenes for instance) but not much anything else.

It is also useful for keeping the DOF narrow ie moving from f4 to f2.8 just by chnging the iso from 100 to 50

I am taking some portraits tomorrow - I will take them at iso50 to see if they are better

Good point, so other than exposure related situations (longer exposures or faster F stops), minor IQ changes...

[briansquibb]

In film, you are correct, but in digital, until they make it an actual default setting and not an expanded setting, you will not see any less noise, but you may see more room for highlight recovery in post production.  It would be nice if Canon/nikon really developed this ISO to match the saturation and buttery smoothness of the old velvia films and the like... as of now, it's good if you need to have longer exposures (running water scenes for instance) but not much anything else.

It is also useful for keeping the DOF narrow ie moving from f4 to f2.8 just by chnging the iso from 100 to 50

I am taking some portraits tomorrow - I will take them at iso50 to see if they are better

Good point, so other than exposure related situations (longer exposures or faster F stops), minor IQ changes...

DxO show marginally better figures at iso 50 than iso100. Compare the 5D2, 1d4, 1ds3 and 7D - they all show an improvement - which matches my subjective observation with the 5S2. Tomorrow I will be using the 1Ds3 - I will post a sample if wanted - but I suspect the interweb will mask the difference

[awinphoto]

In film, you are correct, but in digital, until they make it an actual default setting and not an expanded setting, you will not see any less noise, but you may see more room for highlight recovery in post production.  It would be nice if Canon/nikon really developed this ISO to match the saturation and buttery smoothness of the old velvia films and the like... as of now, it's good if you need to have longer exposures (running water scenes for instance) but not much anything else.

It is also useful for keeping the DOF narrow ie moving from f4 to f2.8 just by chnging the iso from 100 to 50

I am taking some portraits tomorrow - I will take them at iso50 to see if they are better

Good point, so other than exposure related situations (longer exposures or faster F stops), minor IQ changes...

DxO show marginally better figures at iso 50 than iso100. Compare the 5D2, 1d4, 1ds3 and 7D - they all show an improvement - which matches my subjective observation with the 5S2. Tomorrow I will be using the 1Ds3 - I will post a sample if wanted - but I suspect the interweb will mask the difference

We always love pictures... if you have the time and energy, 100% crops could be fun to see differences. 

[picture-this]

Thanks again for the helpful replies!!

[Janco]

I'm wondering too why ISO 50 isn't in the standard ISO range of the 5DIII...

No extra noise, but since it's 'pulled' you effectively lose a stop of highlights.

So with ISO 50 you lose some highlights, but I can't help thinking pictures shot with ISO 50 can't be worse than those shot with ISO 25600, which is in the standard settings... Of course I know, it's easy to enable ISO 50 but I'm just wondering if those images would be affected that much that it really needs to be handled with care?

On the other hand, are there any situations where ISO 50 would be a solution where ND filters wouldn't fit?

[briansquibb]

I'm wondering too why ISO 50 isn't in the standard ISO range of the 5DIII...

No extra noise, but since it's 'pulled' you effectively lose a stop of highlights.

So with ISO 50 you lose some highlights, but I can't help thinking pictures shot with ISO 50 can't be worse than those shot with ISO 25600, which is in the standard settings... Of course I know, it's easy to enable ISO 50 but I'm just wondering if those images would be affected that much that it really needs to be handled with care?

On the other hand, are there any situations where ISO 50 would be a solution where ND filters wouldn't fit?

Iso 50 is not worse than iso 100 so no care is needed