# ISO 160 vs. 100



## Quasimodo (Oct 23, 2014)

I think it was in the Jeff Cable review (reviews are pouring out now) of the 7DII where he made claims that ISO 160 on Canon cameras are better than ISO 100. I find this strange. Guided by earlier discussions on this forum I was led to believe that ISO 100 is the lowest (most clean) natural setting for Canon cameras, and shooting at the optional ISO 50 would clipping the highlights and affect the DR. 

However, I am a simple guy, and if I am told by credible sources that 160 is the magic number for shots where you want a maximum clean image (where conditions allow you), that is then what I will shoot at 

Any thoughts/insights?


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## Maui5150 (Oct 23, 2014)

You can seer here:

http://vimeo.com/23082874

Or here:

http://indigoverse.com/the-truth-about-native-iso-for-canon-dslrs/

I did similar tests and found the same at the lower end. 

My understanding that the 1/3rd stops are pushed and the 1/3rd stops pulled. the ISO 160, 320, 640 seem to be slightly underexposed, but a lot less noise. This may mean you do trade some DR.

For the video example, I would have liked to see them have done 2/3rd jumps i.e. 100, 160, 200, 320, 400, 640.

No question from what I have seen and what the video shows 125 is more noisy than 160, 250 more noisy than 320, and 500 more noisy than 640.

Whether you see 160 as less noise? that remains to be seen, but to my eyes (and some of the charts posted in another thread, 160 looks a little less noisy than 100


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## Coldhands (Oct 23, 2014)

Maui5150 has it right.

ISO 160 generally appears to exhibit less noise that ISO 100 or 125 (same applies for multiples thereof) because it is actually a "pulled" ISO 200 exposure. Because the whole image is being darkened, this tends to hide the noise. The opposite is true of ISO 125, as it is a "pushed" ISO 100 exposure.

The downside of using the pulled ISOs is a lower dynamic range, although the difference is likely to be academic.

Also worth noting: you may have heard that ISO 160 is the "native" sensitivity of Canon sensors, but this is a misconception due to misinterpretation of the results described above.


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## Maui5150 (Oct 23, 2014)

Not sure I have it right:

Also have seen this.

http://photocascadia.wordpress.com/2011/05/13/canon-eos-5d-mark-ii-iso-noise-test/

In the tests like I posted, the noise seems to be called pattern read noise so more an artifact that appears when doing this kind of lens cap on test.

I think when all is said and done, if you shoot 100, 200, etc you get the most information in your image.
If you shoot 160, 320, etc, you are shooting at 200, 400, etc, but then stopped down 20% and this appears to "clean" some of the pattern noise.

The test I haven't seen and what might be interesting to try is looking at long exposures at night and sensor noise from the sensor heating up. i.e. shooting 640 for 3 seconds versus for 400 for 5 seconds


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## 2n10 (Oct 23, 2014)

I liked the bloggers conclusions. ETTR and then ITTR to get you best results all without blowing out your highlights of course.

Isn't that what most folks advocate when you first learn how to use a digital camera?


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## Marsu42 (Oct 23, 2014)

Maui5150 said:


> I think when all is said and done, if you shoot 100, 200, etc you get the most information in your image.
> If you shoot 160, 320, etc, you are shooting at 200, 400, etc, but then stopped down 20% and this appears to "clean" some of the pattern noise.



+1, after shooting at iso160-multiples for some time I came to the conclusion that it isn't worth the hassle... and you cannot just put all sensors in one basket, a 18mp crop sensor on the old 7d1 will behave in a very different way than the latest clean, ff 6d

For other in-depth analysis by the Magic Lantern devs, read this thread "Do have iso160-multiples have more dr & less noise?": http://www.magiclantern.fm/forum/index.php?topic=9867.0


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## neuroanatomist (Oct 23, 2014)

Quasimodo said:


> Any thoughts/insights?



You have a 1D X, so I wouldn't worry about it. The 1D X uses a different analog amplifier setup, note the 'jagged' plot of noise vs. ISO for the 7D and 5DIII (with troughs at 160 multiples), vs. the 'smooth' (and overall lower) plot for the 1D X.


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## sedwards (Oct 23, 2014)

very interesting chart Neuro. do you know if there is a similar one for the 70D and 6D ?


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## drmikeinpdx (Oct 23, 2014)

If you want to know more about the work of William Claff, you can follow this link:

http://home.comcast.net/~nikond70/index.htm

He has a number of charts that apply to Canon sensors, mixed in with a lot of Nikon data.


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## Coldhands (Oct 23, 2014)

neuroanatomist said:


> Quasimodo said:
> 
> 
> > Any thoughts/insights?
> ...



Very interesting. Is this because the 1D X applies the gain at an analogue stage for each ISO, instead (I presume) of for multiples of ISO 100 only, followed by digital push/pull on other sensors? If so that is surprising, as I would have thought such behavior is a product of the sensor architecture shared by all 500 nm process DSLR sensors.


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## neuroanatomist (Oct 23, 2014)

Coldhands said:


> neuroanatomist said:
> 
> 
> > Quasimodo said:
> ...



Others know more about this than me, but I believe the signal amplifiers are off-die (also accounting for 'amp glow'), and the 1D X has separate analog amplifiers for the 'tweener' ISOs whereas other Canon bodies do only full-stop analog amplification with digital push/pull for the 'tweener' settings.


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## Maui5150 (Oct 23, 2014)

neuroanatomist said:


> Quasimodo said:
> 
> 
> > Any thoughts/insights?
> ...



Is the 1Dx native 200 ISO? From the charts it looks like 200 is slightly better


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## neuroanatomist (Oct 23, 2014)

I'm pretty sure the native base ISO is 100 (or slightly less, according to DxO) for the 1D X.


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## Quasimodo (Oct 23, 2014)

While I have a bit of difficulty of understanding all of the kind answers here (technological ineptitude), I am to understand (Neuro) that on my 1Dx Iso 100 is the optimal setting?! And I guess that the charts used here are based on empirical evidence, hence it would be impossible to say beforehand what the correct value for the 7DII would be, except than low?


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## neuroanatomist (Oct 23, 2014)

Quasimodo said:


> While I have a bit of difficulty of understanding all of the kind answers here (technological ineptitude), I am to understand (Neuro) that on my 1Dx Iso 100 is the optimal setting?! And I guess that the charts used here are based on empirical evidence, hence it would be impossible to say beforehand what the correct value for the 7DII would be, except than low?



On the 1D X there's really not much difference at any ISO from 100 - 400. No way to know for sure about the 7DII, but I'd guess it'll be more like the 5DIII/7D.


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## Quasimodo (Oct 23, 2014)

neuroanatomist said:


> Quasimodo said:
> 
> 
> > While I have a bit of difficulty of understanding all of the kind answers here (technological ineptitude), I am to understand (Neuro) that on my 1Dx Iso 100 is the optimal setting?! And I guess that the charts used here are based on empirical evidence, hence it would be impossible to say beforehand what the correct value for the 7DII would be, except than low?
> ...



Thanks


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## jrista (Oct 23, 2014)

In my experience, the differences in noise for the full and +1/3rd (push) stops are not really enough to get worried about for current Canon generation cameras. I have noticed that the 2/3rd (-1/3rd or pull) stops are a bit noisier, however it's still usually not enough to worry about.


Older 18mp APS-C parts had more problems with noise, and the 2/3rd pull stops were pretty noisy. I don't know about older FF parts. So long as your using a current model, however, I simply don't worry about it. Canon read noise is high, and it's high no matter what (at lower ISOs)...a third stop change in high read noise isn't going to change things much. At higher ISOs, the shift with third stops is less significant, and so doesn't matter at all.


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## Don Haines (Oct 24, 2014)

jrista said:


> In my experience, the differences in noise for the full and +1/3rd (push) stops are not really enough to get worried about for current Canon generation cameras. I have noticed that the 2/3rd (-1/3rd or pull) stops are a bit noisier, however it's still usually not enough to worry about.
> 
> 
> Older 18mp APS-C parts had more problems with noise, and the 2/3rd pull stops were pretty noisy. I don't know about older FF parts. So long as your using a current model, however, I simply don't worry about it. Canon read noise is high, and it's high no matter what (at lower ISOs)...a third stop change in high read noise isn't going to change things much. At higher ISOs, the shift with third stops is less significant, and so doesn't matter at all.



For both the 5D2 and the 60D you could easily detect the differences in noise with the "dark frame" test, but with actual photos there wasn't any noticeable difference between adjacent 1/3 stops...


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## jrista (Oct 24, 2014)

Don Haines said:


> jrista said:
> 
> 
> > In my experience, the differences in noise for the full and +1/3rd (push) stops are not really enough to get worried about for current Canon generation cameras. I have noticed that the 2/3rd (-1/3rd or pull) stops are a bit noisier, however it's still usually not enough to worry about.
> ...




I see more noise in normal shots with the 2/3rd stop settings...no dark frame required.


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## bret (Mar 6, 2015)

I did some test images on my 5D2 by taking a black frame with the shutter cap on at each ISO and then increasing them by the same amount to more easily see the noise. I always shoot at increments of 160.


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## Marsu42 (Mar 6, 2015)

neuroanatomist said:


> On the 1D X there's really not much difference at any ISO from 100 - 400.



Same on 6d, "thanks" to Canon's read noise problem there's hardly any reason to shoot at base iso unless the shutter speed has been maxed out.



bret said:


> I did some test images on my 5D2 by taking a black frame with the shutter cap on at each ISO and then increasing them by the same amount to more easily see the noise. I always shoot at increments of 160.



Interesting, esp 640/800 ... but I'd say it might be a bit different on newer cameras. Personally, I'd be hesitant as it's not only about noise with lens cap shots, but about color fidelity and post-processing elasticity which afaik are better at lower base iso settings even on full frame sensors.


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## ejenner (Mar 9, 2015)

I thought this craze had died an appropriate death, but anyway, OK, true read noise is lower at ISO160. But I for one don't tend to take many shots of my lens cap.

Instead of asking the question and getting a bunch of 'facts' that may or may not be relevant to your actual shooting, why not test it yourself with the type of photography you do?

If you can't tell the difference, then don't worry about it. If you can, use what you think is best.

BTW the lens cap shots above show that ISO 320 has lower read noise than ISO 100. Now if you can't tell the difference between those in real photos, then just shoot at whatever ISO you want.


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## adventureous (Mar 12, 2015)

It seems popular in video. Here Vincent Laforet shows the setup for 5dII and 5dIII.

http://blog.vincentlaforet.com/2012/03/12/setting-up-your-canon-5d-mkii-and-mkiii/


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## martti (Mar 15, 2015)

Am I misuderstanding or does that curve mean that on 5DIII you are OK up to 800 ISO after which the noise starts to grow? That would certainly simplify things...

Now, I do not see any standard deviations here nor 'n' so I take it this is the data of one single camera of each brand. The slight curvatures may not be significant at all.


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## Marsu42 (Mar 15, 2015)

martti said:


> Am I misuderstanding or does that curve mean that on 5DIII you are OK up to 800 ISO after which the noise starts to grow? That would certainly simplify things...



Not quite, lookie here for the data: http://www.sensorgen.info/CanonEOS-5D-Mark-III.html

But for practical purposes and non-lens-cap shots, on recent ff Canon cameras I'd say the "It's really a wash" area is from 100-400, that's why I'd rather shoot with 400 and higher shutter speed for anything that moves. You can extend this area to 800 if you accept a little drop in color fidelity. Just my experience, mind you.


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## martti (Mar 15, 2015)

Of course that makes sense.
Still, I have a bit of a hard time looking at a curve where there is no mention of the methods how it was got.
Is it theoretical or is it measured. If it is measured, how many cameras were tested? What about the statistics? Was the value achieved at 160 ISO statistically different (p<0.05) from the value at 400 ISO?

And if it was, so what? 
Personally, I have noticed that a monopod makes the pictures _sharper_ no matter what _lense_ I am using when shooting in available light inside. Which sort of lines up with your experience, doesn't it.


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## Marsu42 (Mar 15, 2015)

martti said:


> Still, I have a bit of a hard time looking at a curve where there is no mention of the methods how it was got.



It's data from DxO, and general opinion is that their pure *measurements* are just fine, other than the *aggregated* variables and the interpretations of them (which favor Sonikon).



martti said:


> Personally, I have noticed that a monopod makes the pictures _sharper_ no matter what _lense_ I am using when shooting in available light inside. Which sort of lines up with your experience, doesn't it.



Yes, imho the shutter speed or other means of camera shake reduction is *hugely* underestimated. IS helps to get "good" pictures, but it cannot compensate fast enough if you re-frame so you get more sharpness at 100% crop with other means like a clumsy monopod.


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