Fujifilm Dynamic Range Use

[jcdeboever]

I found this very informative. Never really understood how it worked until I stumbled across this easy to understand guide.

Fujifilm Dynamic Range Settings Explained: How to Use D-Rng

 

[Ysarex]

He has an inkling of what's going on but he's got problems explaining it. I suspect due to some fundamental misconceptions about ISO. I'd have to look closer at his blogs but I suspect he's making the real common mistake of confusing what ISO is with how it's often implemented. For example from the article: "D-Rng underexposes by reducing the sensor output during the exposure. The sensitivity of the sensor isn’t dialed down, just the exposure of the RAW capture, using ISO." He's trying but "underexposing by reducing the sensor output" makes no sense. Sensor output is reduced by underexposure.

He's trying to explain that Fuji cameras implement the DR200/400 functions by first requiring that you raise the camera ISO setting by at least one or two stops above base ISO and that the camera then avoids ISO clipping in the raw file by not applying either one or two stops of analog amplification when passing the sensor signal to the ADC. He needs to stop confusing himself by trying to explain that as some form of underexposure.

When he addresses raw files ("Does D-Rng affect the RAW file?"), He's just plain wrong. The answer is yes; the camera reduces analog amplification by one or two stops when writing the raw file. And it certainly does not depend on the raw converter you use.

Joe

 

[Mike Drone]

Thanks for the info, I love additional resources =]

 

[jcdeboever]

Thanks for the clarification Joe, I was hoping you'd chime in. I did think his explanation was off somewhat but when I seen the jpegs, it clarified some things in my mind as to the settings.

 

[Ysarex]

Thanks for the clarification Joe, I was hoping you'd chime in. I did think his explanation was off somewhat but when I seen the jpegs, it clarified some things in my mind as to the settings.

He did better than many who I've seen try and address that camera function. His root problem is understanding ISO. I went back and took a quick look at one of his beginner courses. He defines ISO as amplification of the digital signal. He says; "What the sensor does is it collects that light, converts it to a digital signal, amplifies it, and then sends it to the processor for processing. Now that amount of amplification is called ISO."

That's in fact better than what we find in most of these types of blog presentations where they just say that ISO adjusts the sensor's light sensitivity. But he's defining ISO by a common method of implementation. (And he's got that wrong. How do you amplify a digital signal?) In many cameras ISO is implemented by amplifying the analog signal (voltage) from the sensor before it's converted to digital values. In other cameras the digital values are scaled up before being processed into an RGB image. In other cameras ISO is implemented directly in processing the digital values. Confusing how it's done with what it is leads him to this unfortunate conclusion in the DR article when explaining DR400%: "Press the shutter with ISO800 and the capture will happen at an ISO of 200 (really underexposed)." One of those; I know what he's trying to say but saying it that way is a problem. With the camera set to DR400% and an ISO of 800 the camera will produce an expected normal lightness JPEG (not really underexposed). With DR400% the camera implements ISO differently than it does with DR100% but the end result remains ISO compliant. The camera is not making the capture at ISO 200.

Now is where raw files come in. In cameras (most) that implement ISO by amplifying the sensor's analog signal the end result of that amplification is baked-in to the digital values in the raw file. Fuji's DR modes withhold one or two stops of that analog signal amplification and so that absolutely shows in the raw files -- the digital values are all commensurately reduced. The DR modes affect raw files. This is where his thinking gets twisted. By defining ISO as signal amplification he's led to conclude that the capture is really ISO 200 (DR400%) even though the camera is set to ISO 800. The authors of the ISO standard that applies, ISO 12232:2019, anticipated guys like John Peltier here and took the trouble to explicitly write in the standard; "ISO speed and ISO speed latitude values shall not be reported for raw images, however, because with raw images processing that affects the values has not been performed."

Joe

 

[Tropicalmemories]

Thanks for the clarification Joe, I was hoping you'd chime in. I did think his explanation was off somewhat but when I seen the jpegs, it clarified some things in my mind as to the settings.

He did better than many who I've seen try and address that camera function. His root problem is understanding ISO. I went back and took a quick look at one of his beginner courses. He defines ISO as amplification of the digital signal. He says; "What the sensor does is it collects that light, converts it to a digital signal, amplifies it, and then sends it to the processor for processing. Now that amount of amplification is called ISO."

That's in fact better than what we find in most of these types of blog presentations where they just say that ISO adjusts the sensor's light sensitivity. But he's defining ISO by a common method of implementation. (And he's got that wrong. How do you amplify a digital signal?) In many cameras ISO is implemented by amplifying the analog signal (voltage) from the sensor before it's converted to digital values. In other cameras the digital values are scaled up before being processed into an RGB image. In other cameras ISO is implemented directly in processing the digital values. Confusing how it's done with what it is leads him to this unfortunate conclusion in the DR article when explaining DR400%: "Press the shutter with ISO800 and the capture will happen at an ISO of 200 (really underexposed)." One of those; I know what he's trying to say but saying it that way is a problem. With the camera set to DR400% and an ISO of 800 the camera will produce an expected normal lightness JPEG (not really underexposed). With DR400% the camera implements ISO differently than it does with DR100% but the end result remains ISO compliant. The camera is not making the capture at ISO 200.

Now is where raw files come in. In cameras (most) that implement ISO by amplifying the sensor's analog signal the end result of that amplification is baked-in to the digital values in the raw file. Fuji's DR modes withhold one or two stops of that analog signal amplification and so that absolutely shows in the raw files -- the digital values are all commensurately reduced. The DR modes affect raw files. This is where his thinking gets twisted. By defining ISO as signal amplification he's led to conclude that the capture is really ISO 200 (DR400%) even though the camera is set to ISO 800. The authors of the ISO standard that applies, ISO 12232:2019, anticipated guys like John Peltier here and took the trouble to explicitly write in the standard; "ISO speed and ISO speed latitude values shall not be reported for raw images, however, because with raw images processing that affects the values has not been performed."

Joe

Thank you for this detailed explanation, although to be honest I still don't really understand what the DR settings are doing.

 

[Space Face]

There's some really great information and advice in this place for sure.

 

[jcdeboever]

Thanks for the clarification Joe, I was hoping you'd chime in. I did think his explanation was off somewhat but when I seen the jpegs, it clarified some things in my mind as to the settings.

He did better than many who I've seen try and address that camera function. His root problem is understanding ISO. I went back and took a quick look at one of his beginner courses. He defines ISO as amplification of the digital signal. He says; "What the sensor does is it collects that light, converts it to a digital signal, amplifies it, and then sends it to the processor for processing. Now that amount of amplification is called ISO."

That's in fact better than what we find in most of these types of blog presentations where they just say that ISO adjusts the sensor's light sensitivity. But he's defining ISO by a common method of implementation. (And he's got that wrong. How do you amplify a digital signal?) In many cameras ISO is implemented by amplifying the analog signal (voltage) from the sensor before it's converted to digital values. In other cameras the digital values are scaled up before being processed into an RGB image. In other cameras ISO is implemented directly in processing the digital values. Confusing how it's done with what it is leads him to this unfortunate conclusion in the DR article when explaining DR400%: "Press the shutter with ISO800 and the capture will happen at an ISO of 200 (really underexposed)." One of those; I know what he's trying to say but saying it that way is a problem. With the camera set to DR400% and an ISO of 800 the camera will produce an expected normal lightness JPEG (not really underexposed). With DR400% the camera implements ISO differently than it does with DR100% but the end result remains ISO compliant. The camera is not making the capture at ISO 200.

Now is where raw files come in. In cameras (most) that implement ISO by amplifying the sensor's analog signal the end result of that amplification is baked-in to the digital values in the raw file. Fuji's DR modes withhold one or two stops of that analog signal amplification and so that absolutely shows in the raw files -- the digital values are all commensurately reduced. The DR modes affect raw files. This is where his thinking gets twisted. By defining ISO as signal amplification he's led to conclude that the capture is really ISO 200 (DR400%) even though the camera is set to ISO 800. The authors of the ISO standard that applies, ISO 12232:2019, anticipated guys like John Peltier here and took the trouble to explicitly write in the standard; "ISO speed and ISO speed latitude values shall not be reported for raw images, however, because with raw images processing that affects the values has not been performed."

Joe

Thank you for this detailed explanation, although to be honest I still don't really understand what the DR settings are doing.

If you click on the link in the OP, the pics show you and possibly when to use. Doesn't get any simpler for me. I can think of two images I took a few weeks ago that knowing this could have helped.