# Question regarding ISO 50 on 5D III



## picture-this (Mar 15, 2012)

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!


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## neuroanatomist (Mar 15, 2012)

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


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## JoeDavid (Mar 15, 2012)

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...


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## briansquibb (Mar 15, 2012)

JoeDavid said:


> 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


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## picture-this (Mar 15, 2012)

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?


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## JoeDavid (Mar 15, 2012)

picture-this said:


> 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...


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## nvsravank (Mar 15, 2012)

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?


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## awinphoto (Mar 15, 2012)

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.


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## briansquibb (Mar 15, 2012)

awinphoto said:


> 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


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## awinphoto (Mar 15, 2012)

briansquibb said:


> awinphoto said:
> 
> 
> > 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.
> ...



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


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## briansquibb (Mar 15, 2012)

awinphoto said:


> briansquibb said:
> 
> 
> > awinphoto said:
> ...



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


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## awinphoto (Mar 15, 2012)

briansquibb said:


> awinphoto said:
> 
> 
> > briansquibb said:
> ...



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


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## picture-this (Mar 15, 2012)

Thanks again for the helpful replies!!


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## Janco (Apr 1, 2012)

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



neuroanatomist said:


> 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?


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## briansquibb (Apr 1, 2012)

Janco said:


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



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


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## eyeland (Apr 2, 2013)

Today while doing a test of low iso noise in shots with blue skies and clouds, I noticed that when PP, the shots at 50 ISO seem t behave quite different than any other low ISO - namely coming out more saturated with more "pop"
What might explain this?
I will do a little further testing today and post a few examples.
Edit: the strength of the effect I (thought) I saw was probably due to user error as I can't seem to replicate it...
Still, after reading endless claims about ISO, I am still not sure about the pros and cons of native vs non-native...


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## bdeutsch (Apr 2, 2013)

Thanks for the reminder...I basically forgot the 5DIII had ISO 50 because the ISO 50 on my previous camera (5D) looked awful and I never used it. Got to go take some test shots now.


Actor Headshots NYC | Gotham Family Photos | NY Wedding Photographer


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## Sporgon (Apr 2, 2013)

Well as I understand it ISO 50 (L) is ISO 100 over exposed by 1 stop and then processed back down to correct exposure. 

So, if you're in the 'ETTR' camp it's helping you out. 

Actually, as long as I'm not loosing highlights I like it. 

(Which means I am probably a closet ETTR practitioner )


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## kbmelb (Apr 2, 2013)

Pulls are always better than a push as far as noise goes. Just so long as you don't over expose in the first place and need to retrieve high lights 50 should be fine. Although if you are pushing shadows in post you may not have the detail you need.


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## pedro (Apr 2, 2013)

Just took some ISO 50, F/22 photographs last week. A very useful mode, that allows more than 1 sec of exposure at 5.30 p.m. in spring.




Z96A3597bALTTLKLEINDefMASTER by Peter Hauri, on Flickr


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## eyeland (Apr 3, 2013)

Sporgon said:


> Well as I understand it ISO 50 (L) is ISO 100 over exposed by 1 stop and then processed back down to correct exposure.
> 
> So, if you're in the 'ETTR' camp it's helping you out.




ahh ofc, that would explain why I only saw a benefit on a specific scene. This would also mean that native vs non-native iso is relevant to consider if practicing ETTR?


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## Sporgon (Apr 3, 2013)

eyeland said:


> Sporgon said:
> 
> 
> > Well as I understand it ISO 50 (L) is ISO 100 over exposed by 1 stop and then processed back down to correct exposure.
> ...



Good point. 

The answer is yes, because if you exposed to the right by say two thirds whilst in (L) you would actually be over exposing by one and two thirds EV. 

Some have suggested that if you're shooting in RAW then ISO 50 (L) is pointless because you can just shoot ISO 100 and over expose by one full EV (stop), and then post process down. I disagree as if you do this you are lumbered with all your files showing one EV over exposure. IMO much better to shoot in L, gain from the benefit of ETTR, and allow the camera program to bring files back to 'correct' exposure, but you have within there the better info for darker areas.

The caveat of course is that just as when practicing ETTR, when shooting in (L) the photographer must judge the strength of highlights because you will be further over exposing them.


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## eyeland (Apr 3, 2013)

Fully understood and agreed.
By "non native ISO" I was however also referring to ISO values such as 160 and 320, as these are pulled (similar to 50?) in contrast to eg. 125 which is claimed to be pushed.
I am trying to figure out if the inclusion of pulled ISO values make ETTR less useful


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## Sporgon (Apr 3, 2013)

eyeland said:


> Fully understood and agreed.
> By "non native ISO" I was however also referring to ISO values such as 160 and 320, as these are pulled (similar to 50?) in contrast to eg. 125 which is claimed to be pushed.
> I am trying to figure out if the inclusion of pulled ISO values make ETTR less useful




Sorry, I read your response as just relating to 'L' and 'H'; perhaps that's because I know about those ! 

I am not so sure of my facts with intermediate ISOs, but from what I do know, again you raise a very valid point. 

If ISO 160 _is_ pulled from 200, ie it is just ISO 200 over exposed by one third of a stop and reduced back to 'correct' exposure in camera, then the same principle will apply. Conversely if 125 _is_ pushed one third from 100 the principle applies in reverse: you'd be already under exposing by one third so ETTR would have to be increased to compensate. 

By the same principle ISO 160 would then have one third less EV latitude ( the dreaded DR ) than 200, but the test graphs don't show this. 

But I am not sure of my facts on these 'non native' ISOs. I've read that people claim there is less noise at ISO 160 than 100, but I have not found this to be the case. However I have found that ISO 50 (L) _can_ give smoother data than 100.


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## 3kramd5 (Apr 3, 2013)

Sporgon said:


> But I am not sure of my facts on these 'non native' ISOs. I've read that people claim there is less noise at ISO 160 than 100, but I have not found this to be the case. However I have found that ISO 50 (L) _can_ give smoother data than 100.



I've not noticed a marked difference between 100 and 160, but this chart is worth a look.

http://home.comcast.net/~NikonD70/Charts/RN_ADU.htm#EOS%205D%20Mark%20II_14


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## neuroanatomist (Apr 3, 2013)

3kramd5 said:


> I've not noticed a marked difference between 100 and 160, but this chart is worth a look.
> 
> http://home.comcast.net/~NikonD70/Charts/RN_ADU.htm#EOS%205D%20Mark%20II_14



Indeed. All the recent/current Canon bodies except the 1D X have that sawtooth pattern.


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## eyeland (Apr 3, 2013)

3kramd5 said:


> http://home.comcast.net/~NikonD70/Charts/RN_ADU.htm#EOS%205D%20Mark%20II_14


Thank you


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## 3kramd5 (Apr 3, 2013)

neuroanatomist said:


> 3kramd5 said:
> 
> 
> > I've not noticed a marked difference between 100 and 160, but this chart is worth a look.
> ...



Yep, it's interesting how relatively flat the 1Dx is before about 1600ISO.

The idea that intermediate isos are pushed or pulled makes a little more sense to me than something at the amp level ("The shape of the curve can tell you something about the amplifier circuitry of the camera"), but I wonder why they'd take a completely different approach with the 1Dx.


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## Pi (Apr 3, 2013)

It is ETTR. Unless you blow the highlights (and with a "normal" DR scene, there is plenty of highlight room), you get about 1 step lower noise. This means smoother tonal gradations, better response to more extreme pp, WB tweaks, vignetting corrections, etc. In critical situations, I would take a shot at ISO 100 as well, just in case.


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## eyeland (Apr 3, 2013)

also interesting how the 1DX noise drops at ISO 200? can't wait to get my hands on one


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## TrumpetPower! (Apr 3, 2013)

I see lots of confusion here.

Except for the EXIF flag indicating exposure, the RAW file you'll get with ISO50 @ f/8 @ 1/400 will be exactly the same as the one you'll get at ISO100 @ f/8 @ 1/400. The only difference is that, if the camera's meter tells you that the proper exposure is ISO100 @ f/8 @ 1/400, it'll tell you that you should be exposing the ISO50 shot at f/8 @ 1/200. And, of course, the RAW developers are programmed to invisibly apply a stop of digital pull to the ISO50 shot.

There _will_ be a difference between ISO50 @ f/8 @ 1/200 and ISO100 @ f/8 @ 1/400 -- and it's _that_ difference that people almost always compare.

*BUT!*

There _won't_ be a difference between ISO50 @ f/8 @ 1/200 and ISO100 @ f/8 @ 1/200.

And, of course, there _will_ be a difference in the RAW files between ISO100 @ f/8 @ 1/400 and ISO200 @ f/8 @ 1/400.

Hope that helps clear things up....

Cheers,

b&

P.S. A very similar thing happens with highlight tone priority, except in the opposite direction. The RAW files for a given shutter and aperture will be identical between ISO100 and ISO200 + HTP, but the meter will be different. b&


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## 3kramd5 (Apr 3, 2013)

TrumpetPower! said:


> I see lots of confusion here.
> 
> Except for the EXIF flag indicating exposure, the RAW file you'll get with ISO50 @ f/8 @ 1/400 will be exactly the same as the one you'll get at ISO100 @ f/8 @ 1/400. The only difference is that, if the camera's meter tells you that the proper exposure is ISO100 @ f/8 @ 1/400, it'll tell you that you should be exposing the ISO50 shot at f/8 @ 1/200. And, of course, the RAW developers are programmed to invisibly apply a stop of digital pull to the ISO50 shot.
> 
> ...



So basically you're saying the ISO50 setting only affects metering, not sensitivity? 

If I set up at ISO100, meter dead center, take a photo, and then drop to ISO50 with all else being equal, I'll see the meter move one stop to the left, but the actual picture will be the same?


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## neuroanatomist (Apr 3, 2013)

3kramd5 said:


> So basically you're saying the ISO50 setting only affects metering, not sensitivity?
> 
> If I set up at ISO100, meter dead center, take a photo, and then drop to ISO50 with all else being equal, I'll see the meter move one stop to the left, but the actual picture will be the same?



Metering and the ISO value recorded in the metadata. Assuming you're in manual mode (since in an AE mode, the change from ISO 100 to ISO 50 will result in a compensatory change in aperture or shutter speed to maintain metered exposure), the RAW data file will be the same - an ISO 100 exposure. The jpg file will be pulled down a stop, and when you open the ISO 50 RAW file in an editor, it will display darker than the ISO 100 file, because the RAW editor/converter will pull the exposure down based on the ISO value in the metadata.


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## 3kramd5 (Apr 3, 2013)

neuroanatomist said:


> 3kramd5 said:
> 
> 
> > So basically you're saying the ISO50 setting only affects metering, not sensitivity?
> ...



Seems silly/pointless for manual/raw (how I shoot). Good to know.


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## TrumpetPower! (Apr 3, 2013)

3kramd5 said:


> If I set up at ISO100, meter dead center, take a photo, and then drop to ISO50 with all else being equal, I'll see the meter move one stop to the left, but the actual picture will be the same?



By George, I think he's got it!

Yes. If you ignore the meter, two exposures at the same shutter and aperture but with the one at ISO50 and the other at ISO100 will be identical save for the metadata (and therefore subsequent default processing). So, if you shoot manual and RAW, ISO50 is pointless.

But for those who use autoexposure, and especially for those who shoot JPEG, it can be a very handy tool to have in the toolchest as a quick way to get the benefits of ETTR (at, of course the expense of a stop of headroom) either straight out of the camera or with fewer steps in post-processing.

Cheers,

b&


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## Pi (Apr 4, 2013)

TrumpetPower! said:


> I see lots of confusion here.



I do not.


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## Skirball (Apr 4, 2013)

3kramd5 said:


> neuroanatomist said:
> 
> 
> > 3kramd5 said:
> ...



Indeed, thanks NA.

So, I haven't played with my camera above 25.6k, but I'd assume it's the same situation going above there as well?


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## neuroanatomist (Apr 4, 2013)

Skirball said:


> So, I haven't played with my camera above 25.6k, but I'd assume it's the same situation going above there as well?



Just like the L expansion is a digital pull, the H expansion settings are digital pushes, yes.


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## TrumpetPower! (Apr 4, 2013)

neuroanatomist said:


> Skirball said:
> 
> 
> > So, I haven't played with my camera above 25.6k, but I'd assume it's the same situation going above there as well?
> ...



And, to follow up on neuro's point, because I know somebody will wonder and / or ask...yes, they're equally useless for knowledgeable photographers shooting RAW in manual mode, but they can be useful for those shooting in an autoexposure mode and especially useful for JPEG shooters.

The utility for JPEG shooters is especially pertinent because the 5DIII has such an awesome onboard RAW processor.

If you shoot JPEG in low light, you'd be a bit silly to not enable the H modes. If you shoot RAW and manually expose, there's no point to them.

Cheers,

b&


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