fredmiranda.com
Login

Moderated by: Fred Miranda
  New fredmiranda.com Mobile Site
  New Feature: SMS Notification alert
  New Feature: Buy & Sell Watchlist
  

FM Forums | Sony Forum | Join Upload & Sell

1       2       3              9              end
  

Utility of dynamic range beyond a certain point

  
 
ruthenium
Offline
• • • •
Upload & Sell: On
p.10 #1 · Utility of dynamic range beyond a certain point


jtra wrote:
Cameras usually have lower (or same) read noise (compared to captured data) when they are set for higher for high ISOs, not for lower ISOs.
So relative lower read noise is achieved by using higher ISO (second base ISO, e.g. 640 over using base ISO 100).

You can see read noise increases in this Read noise in DN chart: https://www.photonstophotos.net/Charts/RN_ADU.htm
But relative to captured data it decreases in this Input-referred Read Noise chart: https://www.photonstophotos.net/Charts/RN_e.htm


It sounds as if you refer to the conventional Dual Conversion Gain architecture, that indeed works to reduce read noise at the "second base ISO."

My question to Horshack was about the Dual Gain Output.



Jun 21, 2026 at 08:02 AM
snapsy
Online
• • • • • •
Upload & Sell: On
p.10 #2 · Utility of dynamic range beyond a certain point


ruthenium wrote:
Can you expand on the "lower-noise readout path"?
My thinking is that the A7RVI uses the Dual Gain Output (one optimized for highlights and one optimized for shadows).
Perhaps you mean the same, only use different terminology.
I fully appreciate that "if the two sensors capture the same amount of light the sensor with the lower read noise will have a higher SNR in the deep shadows near the noise floor"
The key question is whether the A7RVI has an intrinsically "lower read noise" when compared to A7RV, or if this "lower read noise" is achieved by applying a lower gain "optimized for shadows".
...Show more

The a7rVI achieves its lower low-iso read noise via DGO, which can apply both low (LCG) and high (HCG) conversion gain to the same signal, merging the two readouts into a single pixel value. The LCG-converted value represents the highlights, midtones, and upper shadows; the HCG-converted value the deep shadows. HCG achieves the lower read noise for its component of the signal via more precise electron counting, as it can apply more divisions of signal over a given voltage range. You can see this described in detail in the original Aptina whitepaper (which applies to DCG sensors in general):

https://www.photonstophotos.net/Aptina/DR-Pix_WhitePaper.pdf



Jun 21, 2026 at 08:02 AM
ruthenium
Offline
• • • •
Upload & Sell: On
p.10 #3 · Utility of dynamic range beyond a certain point


snapsy wrote:
The a7rVI achieves its lower low-iso read noise via DGO, which can apply both low (LCG) and high (HCG) conversion gain to the same signal, merging the two readouts into a single pixel value. The LCG-converted value represents the highlights, midtones, and upper shadows; the HCG-converted value the deep shadows. HCG achieves the lower read noise for its component of the signal via more precise electron counting, as it can apply more divisions of signal over a given voltage range. You can see this described in detail in the original Aptina whitepaper (which applies to DCG sensors in general):

https://www.photonstophotos.net/Aptina/DR-Pix_WhitePaper.pdf


I am not so much interested in the deep technical details of how the DGO is implemented, but more in the question on whether the deep shadow signal - to - read noise ratio is similar in the A7RVI and A7RV.
Now, you state specifically "the HCG-converted value the deep shadows" - that implies both the read noise and any signal in the deep shadows.
Thus, my expectation is that only the "upper shadows" should benefit from the DR increased as a result of the DGO.
Correct?



Jun 21, 2026 at 08:10 AM
snapsy
Online
• • • • • •
Upload & Sell: On
p.10 #4 · Utility of dynamic range beyond a certain point


ruthenium wrote:
I am not so much interested in the deep technical details of how the DGO is implemented, but more in the question on whether the deep shadow signal - to - read noise ratio is similar in the A7RVI and A7RV.
Now, you state specifically "the HCG-converted value the deep shadows" - that implies both the read noise and any signal in the deep shadows.
Thus, my expectation is that only the "upper shadows" should benefit from the DR increased as a result of the DGO.
Correct?


DR is the full tonal range of detectable, non-overflowed signal above a minimum SNR threshold, which means DR can be increased by either reducing the noise near the shadow floor (which is what's SNR-limited) or by increasing the electron holding capacity near saturation (which has plenty of SNR but is "overflow limited"). For the a7rVI it's the former, which means the same signal levels near the shadow floor are read out with lower noise.



Jun 21, 2026 at 08:25 AM
fjablo
Offline
• • • •
Upload & Sell: Off
p.10 #5 · Utility of dynamic range beyond a certain point


Lots of tech talk (and it is impressive technology), yet we still haven't seen a real-world example where this increased DR would come in handy, have we? I guess the original question still stands


Jun 21, 2026 at 08:46 AM
snapsy
Online
• • • • • •
Upload & Sell: On
p.10 #6 · Utility of dynamic range beyond a certain point


fjablo wrote:
Lots of tech talk (and it is impressive technology), yet we still haven't seen a real-world example where this increased DR would come in handy, have we? I guess the original question still stands


https://www.fredmiranda.com/forum/topic/1945915/5#17057193



Jun 21, 2026 at 08:50 AM
RoamingScott
Offline
• • • • • •
Upload & Sell: Off
p.10 #7 · Utility of dynamic range beyond a certain point


Welcome to these 6 characters in every thread they grace.

fjablo wrote:
Lots of tech talk (and it is impressive technology), yet we still haven't seen a real-world example where this increased DR would come in handy, have we? I guess the original question still stands




Jun 21, 2026 at 09:10 AM
 


Search in Used Dept. 

gdanmitchell
Offline
• • • • • • •
Upload & Sell: Off
p.10 #8 · Utility of dynamic range beyond a certain point


tctmp wrote:
While I understand it's a personal choice, this picture looks unnatural to me immediately. The upper band of yellow that's as bright as the sun, I don't think it needs to be a photographer who's heavily engaged in post processing to notice this. People who have seen open space sunsets a few times will likely catch that already.


It is “unnatural,” of course. no human eye and no camera can actually look directly into the sun that way and see everything that is in the photograph. The “natural” experience of looking that direction might be to risk blindness. And the birds would be moving. And the difference in brightness et seen the direct sun and the dark areas at the bottom would be beyond the ability of eyes to perceive.

Maybe I’ll hunt up the original raw later on and show you what the “reality” (from the camera’s perspective) actually looked like. :-)

There’s this idea that the best photographs are “real” and just the result of getting all the settings right and punching the shutter release. A perfect copy of “reality” will emerge from the camera.

But that’s how photography works.

As we’ve discussed in this thread, the camera does not “see” the way that human vision sees, and it is really a lost cause to chase that impossible goal. Cameras stop action. Cameras allow action to blur the subject. Cameras capture image elements that cannot be seen. (For example, color in extremely low light.)

I also agree that those of us who understand post-processing through experience are likely to look at a photograph like this
one, realize that it could not possibly be the results of a simple capture, and speculate about how it was realized. (Do that with Adam’s “Moonrise, Hernandez” sometime…)

As to your aesthetic response to the photograph, I’m fine with that. I’ve learned that there is nothing creative that any of us can do in this world that will be loved by everyone, and I expect that not every photograph will speak to every viewer. :-)

- - -

ruthenium wrote:
1) Preventing or minimizing highlight clipping is achieved by adjusting exposure, not by extending the dynamic range.

2) An extended dynamic range can allow capturing more light. The utility of this is in the shadows, not in the highlights. ..


Conceptually this is right on. In situations where the subject contains a wide dynamic range, strive for a curve where the brightest tones are as close to the right edge as possible (to generalize) without blowing them out and then plan to recover/lighten the darkest tones in post.

Another way to say it is that the goal is to capture the maximum range of usable image data in the file so that you can realize the final image in post.

- - -

Daran wrote:
It is not. It may have eluded you, but I did not write that masks make bad images. Not sure why what I meant wasn't obvious to you, but maybe you just wanted to use me as a segway? If so, I'm sorry I responded.


Here’s what you actually wrote:

Daran wrote:
One mans flaw is another mans feature. By using masks you introduce discontinuities into your processing. Which if overdone (common) is something that makes the result look artificial. A safer and more natural approach (assuming the required DR range isn't too wide) is to limit yourself to monotone continuous transfer curves, where what is brighter consistently remains brighter, just not by as much. The C1 HDR adjustments do just this and tend to work very well for typical scenes with a bright sky. But even there, if you overdo it, the result can look cooked.


Also, I suspect you meant “segue,” not “segway?” ;-)

- - -

fjablo wrote:
Lots of tech talk (and it is impressive technology), yet we still haven't seen a real-world example where this increased DR would come in handy, have we? I guess the original question still stands


That’s a fair point, for sure! (I can’t help you since I have neither the A7r6 nor A7r5, etc.)

I’ll speculate, based on doing a lot of photography with cameras that have various levels of DR capability that…

… the differences between most of the cameras that people want to compare here will be pretty darned trivial, bordering on insignificant in real world photography.

That doesn’t mean that continuing to expand camera dynamic range isn’t a worthwhile endeavor. It just means that each incremental step along the way will often be quite small. The improvement from one model to its successor is rarely earthshaking. The sum improvement since my first digital camera (in the mid-1990s) until today is utterly remarkable.

- - -

I’ll end this post (finally!) and get back to the initial “utility of dynamic range beyond a certain point” question by reprising a context that helps me frame the DR stuff. Relative to DR differences among cameras there are three situations you might encounter:

1. The scene/subject presents a dynamic range no larger than what can be handled by essentially any good camera. This is by far the most common situation.

2. the subject presents a dynamic range that is so large that no current camera (that any of us has access to) can fully handle it in a single exposure. This is a small percentage of shots, but it does happen.

3. The subject presents a dynamic range that is just barely within the range of the best DR camera and just slightly out of range of some alternative camera with incrementally smaller DR and the difference is visible in the final image. This is extremely rare.

Edited on Jun 21, 2026 at 10:51 AM · View previous versions



Jun 21, 2026 at 10:08 AM
Jack Flesher
Offline
• • • •
Upload & Sell: On
p.10 #9 · Utility of dynamic range beyond a certain point


snapsy wrote:
https://www.fredmiranda.com/forum/topic/1945915/5#17057193


Except that particular image is essentially irrelevant to showing an actual photographic need. I believe the point was directed to one extra stop of DR making a good image better, and here I have to agree that nobody’s shown us an example where it does, only the contrary. A lot of theory and measurbating attempting to support the claim, but no images where it actually makes a notable difference.

In theory, more is better, but at a certain point it’s akin to giving you 15 gallons of gasoline when you only have room for 12.



Jun 21, 2026 at 10:14 AM
snapsy
Online
• • • • • •
Upload & Sell: On
p.10 #10 · Utility of dynamic range beyond a certain point


Jack Flesher wrote:
Except that particular image is essentially irrelevant to showing an actual photographic need. I believe the point was directed to one extra stop of DR making a good image better, and here I have to agree that nobody’s shown us an example where it does, only the contrary. A lot of theory and measurbating attempting to support the claim, but no images where it actually makes a notable difference.

In theory, more is better, but at a certain point it’s akin to giving you 15 gallons of gasoline when you only have room for 12.


"Good" images are a matter of opinion. The increase in DR in the example provided is a demonstrated fact.



Jun 21, 2026 at 10:31 AM
fjablo
Offline
• • • •
Upload & Sell: Off
p.10 #11 · Utility of dynamic range beyond a certain point


snapsy wrote:
https://www.fredmiranda.com/forum/topic/1945915/5#17057193


Not a real-world example, rather an immediate delete (no offense, I know you just constructed a test )

Imo this image is incorrectly exposed - approx 2 stops under - which makes your analysis moot. The edit is also unnatural, the window should be much brighter (ideally not completely blown, but much brighter than the interior). Also your later attempt did not get the lighting ratio right.

Here are two real-world examples of interiors with windows:

Kyoto by Felix, auf Flickr

Sant'Andrea della Valle III by Felix, auf Flickr

And to answer my own question: I f*cked up the exposure on the Kyoto image, which is why it has more noise in the shadows than it needs to have. Guess that new sensor tech would have helped here (or me not messing up)

Edited on Jun 21, 2026 at 11:50 AM · View previous versions



Jun 21, 2026 at 11:48 AM
Jack Flesher
Offline
• • • •
Upload & Sell: On
p.10 #12 · Utility of dynamic range beyond a certain point


snapsy wrote:
"Good" images are a matter of opinion. The increase in DR in the example provided is a demonstrated fact.


On this we disagree. To my eyes in this example, the “increase” shown was irrelevant.



Jun 21, 2026 at 11:49 AM
snapsy
Online
• • • • • •
Upload & Sell: On
p.10 #13 · Utility of dynamic range beyond a certain point


fjablo wrote:
Not a real-world example, rather an immediate delete (no offense, I know you just constructed a test )

Imo this image is incorrectly exposed - approx 2 stops under - which makes your analysis moot. The edit is also unnatural, the window should be much brighter (ideally not completely blown, but much brighter than the interior). Also your later attempt did not get the lighting ratio right.

Here are two real-world examples of interiors with windows:

https://live.staticflickr.com/65535/55187429095_81a324dec5_b.jpgKyoto by Felix, auf Flickr

https://live.staticflickr.com/65535/53602072430_0c454a8040_b.jpgSant'Andrea della Valle III by Felix, auf Flickr

And to answer my own question: I f*cked up the exposure on the
...Show more

No offense taken - it was a real photo, taken several years ago for a quick proof to a realtor. I also bracketed the exposure for the final deliverable.



Jun 21, 2026 at 12:04 PM
1       2       3              9              end






FM Forums | Sony Forum | Join Upload & Sell

1       2       3              9              end
    
 

Welcome back
Log in to your account