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High ISO Highlight Protection - Fujifilm and Hasselblad

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bclaff

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So, it turns out that the following three cameras that I have tested perform what I'm going to call "High ISO Highlight Protection":
  • Fujifilm GFX 50S
  • Hasselblad H6D-50c
  • Hasselblad X1D-50c
The Hassselblad models escaped earlier detection :-)

This is a good trend provided the downstream software processing the raw files knows to take advantage.

The principle is that once the camera becomes "ISO Invariant" there is no benefit to raising the analog gain inside the camera.
This means that highlights are not clipped in the Analog to Digital Conversion (ADC) that would otherwise have been clipped.

You can get the same effect on any ISO Invariant camera by underexposing at a lower ISO setting.
But it's nice to see that this is something you don't have to explicitly think about with the above cameras.
 
Is this trend also seen in Fujifilm X- cameras with crop sensors?
 
bclaff said:
So, it turns out that the following three cameras that I have tested perform what I'm going to call "High ISO Highlight Protection":
  • Fujifilm GFX 50S
  • Hasselblad H6D-50c
  • Hasselblad X1D-50c
The Hassselblad models escaped earlier detection :-)

This is a good trend provided the downstream software processing the raw files knows to take advantage.

The principle is that once the camera becomes "ISO Invariant" there is no benefit to raising the analog gain inside the camera.
This means that highlights are not clipped in the Analog to Digital Conversion (ADC) that would otherwise have been clipped.

You can get the same effect on any ISO Invariant camera by underexposing at a lower ISO setting.
But it's nice to see that this is something you don't have to explicitly think about with the above cameras.
Click to expand...
I restated the PDR at my site to be consistent in how a treat this feature.

7ada11830eae4b5c9da266a80ab884da.jpg.png

I'm working on annotating my charts better to indicate "special" ISO settings; stay tuned.

--
Bill ( Your trusted source for independent sensor data at http://www.photonstophotos.net )
 
Last edited:
uMad said:
pepeta said:
Is this trend also seen in Fujifilm X- cameras with crop sensors?
Click to expand...
In cameras with X-Trans I and X-Trans II it's done, with the new X-Trans III only in extended ISOs.
Click to expand...
Actually, I do see it in the X-E1, X-E2,X-Pro2, X-T1, X-T2, and X-T20

And, perhaps a surprise, in the Apple iPhone 7 (!) starting with ISO 200.

Regards,
 
Bill,

Maybe I'm not understanding something about PDR, but in the ISO invariant range, how does it maintain PDR by underexposing?

If it's underexposing, that means the brightness has to be raised in the RAW developer, but doesn't that also raise the shadow noise, and so the dynamic range has to be reduced? I'm very confused about these findings!

--
http://www.flickr.com/photos/andreyew/
 
Last edited:
Andre Yew said:
Bill,

Maybe I'm not understanding something about PDR, but in the ISO invariant range, how does it maintain PDR by underexposing?

If it's underexposing, that means the brightness has to be raised in the RAW developer, but doesn't that also raise the shadow noise, and so the dynamic range has to be reduced? I'm very confused about these findings!
Click to expand...
 
bclaff said:
uMad said:
pepeta said:
Is this trend also seen in Fujifilm X- cameras with crop sensors?
Click to expand...
In cameras with X-Trans I and X-Trans II it's done, with the new X-Trans III only in extended ISOs.
Click to expand...
Actually, I do see it in the X-E1, X-E2,X-Pro2, X-T1, X-T2, and X-T20
Click to expand...
I guess with the new cameras (X-T2, X-T20, X-Pro2) only at extended ISOs if I am right (so everything above ISO 12800). With the older models I think it was until IS 1600.
bclaff said:
And, perhaps a surprise, in the Apple iPhone 7 (!) starting with ISO 200.
Click to expand...
Imo that's how it is supposed to be.
 
Andre Yew said:
Bill,

Maybe I'm not understanding something about PDR, but in the ISO invariant range, how does it maintain PDR by underexposing?

If it's underexposing, that means the brightness has to be raised in the RAW developer, but doesn't that also raise the shadow noise, and so the dynamic range has to be reduced? I'm very confused about these findings!
Click to expand...
It can be a bit confusing.

The raw file has the dynamic range of the lower ISO.

If you push the raw data to the indicated ISO then you'll lose that headroom dynamic range.
But you have the option not to push in that fashion.
Rather than pushing the linear data you might leave it as is and then apply a strong tone curve to the resulting image (or a selective mask, or whatever you choose to do.)

So it's a strategy that simply gives you more post processing flexibility; access to information that is often lost.
 
bclaff said:
bclaff said:
So, it turns out that the following three cameras that I have tested perform what I'm going to call "High ISO Highlight Protection":
  • Fujifilm GFX 50S
  • Hasselblad H6D-50c
  • Hasselblad X1D-50c
The Hassselblad models escaped earlier detection :-)

This is a good trend provided the downstream software processing the raw files knows to take advantage.

The principle is that once the camera becomes "ISO Invariant" there is no benefit to raising the analog gain inside the camera.
This means that highlights are not clipped in the Analog to Digital Conversion (ADC) that would otherwise have been clipped.

You can get the same effect on any ISO Invariant camera by underexposing at a lower ISO setting.
But it's nice to see that this is something you don't have to explicitly think about with the above cameras.
Click to expand...
I restated the PDR at my site to be consistent in how a treat this feature.

7ada11830eae4b5c9da266a80ab884da.jpg.png

I'm working on annotating my charts better to indicate "special" ISO settings; stay tuned.
Click to expand...
So, there's no need to boost ISO past 1600?

Do you know for sure that Adobe hasn't adjusted for this yet (not that I shoot ISO 1600 almost never)?

--
Once you've done fifty, everything else is iffy.
 
Rick Knepper said:
bclaff said:
bclaff said:
So, it turns out that the following three cameras that I have tested perform what I'm going to call "High ISO Highlight Protection":
  • Fujifilm GFX 50S
  • Hasselblad H6D-50c
  • Hasselblad X1D-50c
The Hassselblad models escaped earlier detection :-)

This is a good trend provided the downstream software processing the raw files knows to take advantage.

The principle is that once the camera becomes "ISO Invariant" there is no benefit to raising the analog gain inside the camera.
This means that highlights are not clipped in the Analog to Digital Conversion (ADC) that would otherwise have been clipped.

You can get the same effect on any ISO Invariant camera by underexposing at a lower ISO setting.
But it's nice to see that this is something you don't have to explicitly think about with the above cameras.
Click to expand...
I restated the PDR at my site to be consistent in how a treat this feature.

7ada11830eae4b5c9da266a80ab884da.jpg.png

I'm working on annotating my charts better to indicate "special" ISO settings; stay tuned.
Click to expand...
So, there's no need to boost ISO past 1600?

Do you know for sure that Adobe hasn't adjusted for this yet (not that I shoot ISO 1600 almost never)?

--
Once you've done fifty, everything else is iffy.
Click to expand...
No Adobe hasn't adjusted to this in their current iterations.
 
Rick Knepper said:
bclaff said:
bclaff said:
So, it turns out that the following three cameras that I have tested perform what I'm going to call "High ISO Highlight Protection":
  • Fujifilm GFX 50S
  • Hasselblad H6D-50c
  • Hasselblad X1D-50c
The Hassselblad models escaped earlier detection :-)

This is a good trend provided the downstream software processing the raw files knows to take advantage.

The principle is that once the camera becomes "ISO Invariant" there is no benefit to raising the analog gain inside the camera.
This means that highlights are not clipped in the Analog to Digital Conversion (ADC) that would otherwise have been clipped.

You can get the same effect on any ISO Invariant camera by underexposing at a lower ISO setting.
But it's nice to see that this is something you don't have to explicitly think about with the above cameras.
Click to expand...
I restated the PDR at my site to be consistent in how a treat this feature.

7ada11830eae4b5c9da266a80ab884da.jpg.png

I'm working on annotating my charts better to indicate "special" ISO settings; stay tuned.
Click to expand...
So, there's no need to boost ISO past 1600?

...
Click to expand...
If you keep the same exposure (aperture and shutter) then going past ISO 1600 only has the effect of lightening the out of the camera jpg. That might be helpful to some people.

--
Bill ( Your trusted source for independent sensor data at http://www.photonstophotos.net )
 
Please not that Adobe do scale the exposure correctly beyond ISO 1600. This means that the raw file contains a metadata tag to scale exposure and it is correctly interpreted by ACR. See the attached screenshots comparing the jpegs with the raw files at default settings for ISO 3200, 6400 and 12800. The big problem in ACR at the moment is the very bad rendering at 12800. There is a lot of colour smearing and a severe green colour cast which varies across the tonal range which makes it difficult to remove ( please note that the file is correctly white balanced ). I have seen other examples in different light where the colour cast is magenta.

ISO 3200



982fa864a92d498d90549511e57fa7a5.jpg



ISO 6400





6ba05b1d6f824fd684cb7ab9c9922680.jpg



ISO 12800





03d5b977bf46415f863c431f6f5959e6.jpg
 
The older CCD backs did not have a analog amplifier for iso either. I am not sure about Phase 1, but I am pretty sure that my old H4D-50 takes all pictures at ISO 50, even when using higher ISOs. Even at ISO 50, the meter is calibrated conservatively towards under-exposure: the values are about 1/2 darker than on my DSLR for the same scene.

I find that great, because it gives smoother highlights. The cost is a higher shadow noise, of course.
 
Thanks Bill and uMad for the explanation. I think I understand now, and I was curious if I was missing something. This weekend, I tried this out in a manual way with my D810 shooting an ISO 1600 exposure at ISOs 200 and 400, so 2-3 stops underexposed, and then raising them in Lightroom afterwards with a corresponding exposure slider adjustment, along with a -100 highlights adjustment (it was a pretty large dynamic range scene inside an old church with light coming in from high windows, but dark everywhere else).

As far as noise goes, the results were as expected, but one thing that was a big surprise for me was the malleability of the files. Highlight dodging in Photoshop (using the dedicated dodging brush, but I'm sure curves dodging would be similar too) suddenly had way more headroom before blowing out. When I shot ISO1600 images, there was not much highlight dodging I could do before I'd lose all tonality.

I've been trying to wrap my head around this, and so far I have no idea why this should be the case. It's great because it saves me from buying a D4S, because I had thought I needed a better low-light sensor. Any thoughts on why there'd be more post-processing latitude in the highlights now?
 
what you are talking about is exactly the benefit of isoless cameras (and handling).

You exposed for the brightest relevant highlights, leaving them unharmed (had you increased the ISO you would have clipped them).

Pushing the exposure in post production brightens the image but doesn't clip the highlights, the information is still there to be brought back.

You could even try the same with ISO 64. Noise would be nearly the same and you would have even more dynamic range to work with.

But in this topic it's not about isoless sensors, it's about Fujifilm and Hasselblad using the isoinvariant properties of the sensor, to maintain more dynamic range at higher ISOs.
 
AndreStMaur said:
uMad said:
what you are talking about is exactly the benefit of isoless cameras (and handling).
Click to expand...
I think it is the benefit of not exposing "to the right", but letting some highlights headroom...
Click to expand...
Regardless of whether a camera is ISO Invariant you will always improve image quality (perhaps not visibly) by Exposing To The Right (ETTR).
 
bclaff said:
AndreStMaur said:
uMad said:
what you are talking about is exactly the benefit of isoless cameras (and handling).
Click to expand...
I think it is the benefit of not exposing "to the right", but letting some highlights headroom...
Click to expand...
Regardless of whether a camera is ISO Invariant you will always improve image quality (perhaps not visibly) by Exposing To The Right (ETTR).
Click to expand...
In theory, yes.

But ETTR is one of this things were theory does not match practice, as shown in this thread. If you leave some headroom (here because your camera is "isoless" and does it on its own when choosing anything beyond base ISO), you will notice better highlights, as the o.p. did.

So: do as you want, but I will continue to use my ancient camera at ISO 100, while its base sensitivity is ISO 50 and enjoy better highlight roll-off.
 
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