What I learned about A7rII Dynamic Range today...

[dmward]

... by making a blunder.

I stopped in a village center on my way back from a meeting at just about noon. Sun was out, I had camera set to Av mode, and I thought Auto ISO, with aperture at F8.0. That's my default for walking around with the 24-240. Long story short; I quickly discovered that the ISO was set to 12800. I discovered that when a 2EV bracket all looked over exposed in the EVF. After discovering my error, I redid the shot.

Then, when I got home I had a look in Lightroom and decided to see if I could "save" the over exposed image. Here are the results.

I'm including the full frame and 100% crops of both versions and also the LR develop settings. Sharpening and everything else is at default.

First the 12800 ISO image:



100% crop



100 ISO 100% crop



100 ISO image



Lightroom develop settings



This is not a recommendation to be careless with camera settings.

But is does illustrate how well the sensor is able to handle extreme Expose-to-the-Right. And how little noise is present even at the extreme ISO.

 

[Guy Mancuso]

Pretty damn impressive . Little noisy but to be expected. Nice error / recovery

 

[Jack]

No offense, but I see a whole heckalotta noise in the white paint shadow area under the headlight down through the tire and wheel in the 12800 image -- and pretty ugly noise too -- where the ISO 100 is smooth and clean in that region. My .02 only and just FWIW...

 

[Guy Mancuso]

You know you may have even overexposed slightly more since you ran out of shutter speed in A mode

 

[Guy Mancuso]

No offense, but I see a whole heckalotta noise in the white paint shadow area under the headlight in the 12800 image, while the ISO 100 is smooth and clean there. FWIW...

12,800 ISO bud that's out there in la la land. I don't expect any camera to go that high without noise. Frankly I would never even set a camera that high

 

[dandrewk]

Did you try to de-noise the overexposed image?

I'd love to see that image put through DxO's prime noise removal... when it becomes available for the A7rII.

 

[dmward]

No offense, but I see a whole heckalotta noise in the white paint shadow area under the headlight down through the tire and wheel in the 12800 image -- and pretty ugly noise too -- where the ISO 100 is smooth and clean in that region. My .02 only and just FWIW...

Jack,
Of course there is noise. The reason the camera was at 12600 was because I'd been making some test shots in the house at extreme ISO just to see when the noise became intolerable.

As Guy pointed out, given the ISO the noise is reasonable, even better than expected. Naturally it gets more pronounced as the tones deepen.

At 100% we're talking 26.5 inches on the long side at 300 PPI or 33.33 inches at 240 PPI. At those sizes one will see the noise as shown at 100% at a much closer than normal viewing distance for a print that large.

I'm not suggesting that 12600 ISO without noise reduction is within the realm of normal practice, just that it may be more useful than one would first expect.

- - - Updated - - -

Did you try to de-noise the overexposed image?

I'd love to see that image put through DxO's prime noise removal... when it becomes available for the A7rII.

No noise reduction of any kind.

 

[docmoore]

No offense, but I see a whole heckalotta noise in the white paint shadow area under the headlight down through the tire and wheel in the 12800 image -- and pretty ugly noise too -- where the ISO 100 is smooth and clean in that region. My .02 only and just FWIW...

But ..... Jack its so film like grain! :ROTFL:

I have made these mistakes but tend not to share them.

Bob

 

[dmward]

Here are two versions of the 100% detail with noise reduction:

This one with LR sharpening. Everything is at 50 except detail which is at 80


This one was taken into Photoshop with all sharpening and noise reduction settings at zero then I used Topaz Denoise Raw Light.



I applied LR export sharpening to the JPGs which may have messed them up a bit. They look cleaner on my screen.

 

[Guy Mancuso]

That software is pretty amazing

 

[dmward]

This has turned into a tread discussing Noise Reduction but my main interest in posting this was how impressed I was with the ability to pull back the highlights from a dramatically over exposed image.

Everyone talks about how the Sony cameras seem to be best when a bit underexposed because of the likelihood of highlight blow out.

These were shot at noon in bright sun. Over exposed and there is still that much headroom.
Notice that there is no telltale spike at the extreme right of the histogram, even when the exposure is pulled down to get the brightest pixels below 255.

 

[dmward]

But ..... Jack its so film like grain! :ROTFL:

I have made these mistakes but tend not to share them.

Bob

The grain look is one reason I don't mind noise in high ISO images. I remember what the grain looked like when pushing transparency or B&W film.

I've learned a lot from my mistakes, in photography as well as life, so if I can help someone else learn as well, so much the better.

Now you can go past this screwup to another.

 

[ErikKaffehr]

Hi,

At 12800 most of the noise is coming from the natural variation in the incident number of photons. No one can do much about it. Let's assume

• Base ISO = 100
• Full Well Capacity = 60000
• 18% grey 3 stops below saturation

SNR (Signal to Noise Ratio) will be: 86

• ISO = 12800
• Full Well Capacity = 60000
• 18% grey 3 stops below saturation

SNR will be 7.6

This is simple physics and represent maximum values. Now highlights are exposed higher if the white area is saturation, tehoretically possible SNR would be around 22 in that very area.

It may be possible to raise FWC (Full Well Capacity). Downsampling the image reduces noise.

Vendors can take some liberties with stating ISO-s, as there are several standards, and they can apply noise reduction on the raw files.

But, physics matter a lot…

Best regards
Erik

12,800 ISO bud that's out there in la la land. I don't expect any camera to go that high without noise. Frankly I would never even set a camera that high

 

[dandrewk]

This has turned into a tread discussing Noise Reduction but my main interest in posting this was how impressed I was with the ability to pull back the highlights from a dramatically over exposed image.

Everyone talks about how the Sony cameras seem to be best when a bit underexposed because of the likelihood of highlight blow out.

These were shot at noon in bright sun. Over exposed and there is still that much headroom.
Notice that there is no telltale spike at the extreme right of the histogram, even when the exposure is pulled down to get the brightest pixels below 255.

Agreed. My takeaway is that the information is -available- to be tweaked and massaged. A "lesser sensor" might have rendered the whole thing into a series of blobs - no detail there.

In short, the image is fixable, even with the high potential for blown out highlights. That's pretty awesome.

 

[Guy Mancuso]

This is how I looked at it was the ability to pull it back without posterizing or some other weird effect.

 

[mjm6]

This is how I looked at it was the ability to pull it back without posterizing or some other weird effect.

Exactly... this camera seems to have a soft shoulder to it's response curve before blowing out to 255. That is not a small feat, and when you consider where we were not too long ago, rather spectacular.

This is, I believe, what may be the reason that some people are saying they are getting great B&W conversions out of the camera. A gentle shoulder that feels more like silver than previous generations of digital have.


---Michael

 

[Zlatko Batistich]

That is some ultra-fine & beautiful noise for that ISO. It looks amazing. If those are 100% crops, then we've practically got our noses up to a piece of a 6-foot image (or thereabouts).

 

[dmward]

Sometime in the next couple of days I'm going to make a camera profile using Adobe Profile Editor.
I found that one option when making a profile is to assign a straight gama curve. It makes the image extremely flat looking but provides a lot more edibility in Lightroom or Photoshop.

I have noticed that Canon and Fuji cameras tend to clip the highlights before this.

 

[tashley]

Hi,

At 12800 most of the noise is coming from the natural variation in the incident number of photons. No one can do much about it. Let's assume

• Base ISO = 100
• Full Well Capacity = 60000
• 18% grey 3 stops below saturation

SNR (Signal to Noise Ratio) will be: 86

• ISO = 12800
• Full Well Capacity = 60000
• 18% grey 3 stops below saturation

SNR will be 7.6

This is simple physics and represent maximum values. Now highlights are exposed higher if the white area is saturation, tehoretically possible SNR would be around 22 in that very area.

It may be possible to raise FWC (Full Well Capacity). Downsampling the image reduces noise.

Vendors can take some liberties with stating ISO-s, as there are several standards, and they can apply noise reduction on the raw files.

But, physics matter a lot…

Best regards
Erik

That is scary!

 

[ken_vs_ryu]

Looks film-like to me. :thumbup: