Dynamic Range - What's the trade off?

[John 2]

I was reading the reviews of the new Fuji X70 and one of the reviewers made much of the fact that the in camera dynamic range adjustment works well for high contrast shots. I think most cameras have this option but I never think to use it. I'm also guessing that there is a trade of for increasing the dynamic range of the sensor otherwise why not always have it on max. I'm clueless as to why. Anyone have any knowledge on the subject.

[george013]

I was reading the reviews of the new Fuji X70 and one of the reviewers made much of the fact that the in camera dynamic range adjustment works well for high contrast shots. I think most cameras have this option but I never think to use it. I'm also guessing that there is a trade of for increasing the dynamic range of the sensor otherwise why not always have it on max. I'm clueless as to why. Anyone have any knowledge on the subject.

What is a dynamic range adjustment?

George

[Manfred M]

John - I read somewhere (here I suspect) that this is something that works on jpegs only and is in fact a bit of a "cheat" on Fujifilm's part. I think the source of the information might have been Robin (Black Pearl), but I could be wrong.

[James G]

I shoot with Canon and have no real experience of Fuji.

I believe that 'dynamic range' is synonymous in this instance with a function called 'Auto Lighting Optimiser' i.e capturing (jpg) using specific styles. Since I capture raw, I exercise control over the total usable dynamic range of the capture during first stage processing in Adobe Camera Raw. I understand that 'usable total dynamic range is increased by about 1.2 f-stops using the raw processor rather than 'in camera' picture styles. I think it may be possible to do slightly better by manually tweaking the camera raw defaults, but I have never felt the need.

[Black Pearl]

Think it was me...

This feature is only for jpeg output though with a Fuji that is no bad thing as their jpeg engine is one of the very best with many users never shooting raw. If you follow the Fuji forums and groups it is this jpeg output and the film simulations offered that make the X System so appealing. I will admit that I don't use the jpeg output as much as I should/could but I do like and do use the simulations which are available with raw shooting via LR and ACR. I have used the DR extension feature and it does work remarkable well.

Because modern sensors are almost ISO free - the amount of light hitting the sensor doesn't change with ISO all you do is alter the gain which can be done in camera or in software (with raw files) with very little real difference to the end result - Fuji have a feature where you can run the DR at 100%, 200% or 400% by fiddling with the ISO and exposure.

At 100% the ISO you set is the one the camera uses and the displayed exposure is as it should be.
At 200% the camera ups the base ISO by one stop to 400 ISO, changes the displayed exposure so you get an under exposed by one stop file to hang onto highlight detail then pulls the shadows back via processing.
At 400% the camera changes the underlying ISO by 2 stops so it uses 800 ISO (you have to use this) meaning your file is now two stops under exposed, the highlights have even more detail and the shadows are then brought back to give an end jpeg that looks to have an extended DR.

If you examine the resulting file at high magnification then you can (may) see an increase in noise levels but because modern sensors are very good at 800 ISO and noise reduction application is getting more and more sophisticated the overall file is very usable. Its a neat trick and does work very well so long as you like using the camera with Fuji's jpeg output.

[DanK]

Because modern sensors are almost ISO free - the amount of light hitting the sensor doesn't change with ISO all you do is alter the gain which can be done in camera or in software (with raw files) with very little real difference to the end result

This is a bit off the original topic, but I believe this is only half correct. Regardless of whether a camera is ISO-less, changing ISO never affects the amount of light hitting the sensor. With an ISO-less sensor, you the relationship between ISO and dynamic range is linear from base ISO: you loose one stop of DR for each stop of increased ISO. With other cameras, electronics dominate sensor noise at low ISOs, and the curve is concave down, that is, one looses less than a stop of DR per stop of increased ISO at lower ISOs. Therefore, with ISO-less cameras, boosting the signal in camera and in software are essentially equivalent. In contrast, in other cameras, you will generally get a cleaner image if you boost ISO in camera, up to the ISO level where the camera becomes ISO-less.

You can see a discussion of this and a graphical display by Guillermo Luijk here.

Someone can correct me if I have this wrong.

[rpcrowe]

I am old enough to remember the Broadway Musical Play, "Annie Get Your Gun"...

It contained a song that was very appropriate to the difference between in camera processing of JPEG images and the photographer's post processing of RAW images. The song went. "Anything you can do, I can do better. I can do anything better than you"

[xpatUSA]

<> Regardless of whether a camera is ISO-less, changing ISO never affects the amount of light hitting the sensor. With an ISO-less sensor, the relationship between ISO and dynamic range is linear from base ISO: you [lose] one stop of DR for each stop of increased ISO. With other cameras, electronics dominate sensor noise at low ISOs, and the curve is concave down, that is, one [loses] less than a stop of DR per stop of increased ISO at lower ISOs. Therefore, with ISO-less cameras, boosting the signal in camera and in software are essentially equivalent. In contrast, in other cameras, you will generally get a cleaner image if you boost ISO in camera, up to the ISO level where the camera becomes ISO-less.

You can see a discussion of this and a graphical display by Guillermo Luijk here.

Someone can correct me if I have this wrong . . .

. . . won't be me , excellent post!

I have three truly ISO-less DSLRs and I just love 'em. Even further off-topic, my "ISO-knob" is super-glued in the base-ISO position.

Thanks for the link; all of Luijk's stuff is recommended reading, IMHO.

[Shadowman]

Nikon has active D-Lighting which adds detail to shadows and maintains or controls highlights. If I'm not mistaken Fujifilm is supposed to have the widest dynamic range of all cameras; without the need for any adjustment.

http://www.digitalcameraworld.com/20...nd-highlights/

[george013]

Think it was me...

This feature is only for jpeg output though with a Fuji that is no bad thing as their jpeg engine is one of the very best with many users never shooting raw. If you follow the Fuji forums and groups it is this jpeg output and the film simulations offered that make the X System so appealing. I will admit that I don't use the jpeg output as much as I should/could but I do like and do use the simulations which are available with raw shooting via LR and ACR. I have used the DR extension feature and it does work remarkable well.
Because modern sensors are almost ISO free - the amount of light hitting the sensor doesn't change with ISO all you do is alter the gain which can be done in camera or in software (with raw files) with very little real difference to the end result - Fuji have a feature where you can run the DR at 100%, 200% or 400% by fiddling with the ISO and exposure.

I don't know what ISO free means. Searching the net I find ISO free and ISO less. I think, not sure, they are the same. What I understood is that the result of a picture taken at let's say 800 ISO will be about the same as a picture taken at 200 ISO and give it in PP an exposure correction of +2 stop.

At 100% the ISO you set is the one the camera uses and the displayed exposure is as it should be.
At 200% the camera ups the base ISO by one stop to 400 ISO, changes the displayed exposure so you get an under exposed by one stop file to hang onto highlight detail then pulls the shadows back via processing.

This one I don't understand. I think the camera has a base ISO of 200. To get a underexposed picture with the same settings of S and A the ISO must be 100. Is upping the base to 400 the same?

At 400% the camera changes the underlying ISO by 2 stops so it uses 800 ISO (you have to use this) meaning your file is now two stops under exposed, the highlights have even more detail and the shadows are then brought back to give an end jpeg that looks to have an extended DR.

How can the high lights have more details when the exposure is underexposed?

If you examine the resulting file at high magnification then you can (may) see an increase in noise levels but because modern sensors are very good at 800 ISO and noise reduction application is getting more and more sophisticated the overall file is very usable. Its a neat trick and does work very well so long as you like using the camera with Fuji's jpeg output.

[Manfred M]

Nikon has active D-Lighting which adds detail to shadows and maintains or controls highlights. If I'm not mistaken Fujifilm is supposed to have the widest dynamic range of all cameras; without the need for any adjustment.

http://www.digitalcameraworld.com/20...nd-highlights/

Again as was stated near the top of this thread, this is applicable only to jpegs, so in truth Fujifilm isn't any better or worse than other camera makers in their raw files, but they have developed a software solution to do so in their jpegs.

[Inkanyezi]

It might perhaps be helpful to the OP to explain a bit of DR optimising.

Many cameras have some setting for higher dynamic range, although so far I have not seen any brand other than Nikon that explains how it works - if it works at all, which is doubtful with some models.

Nikon started the race by introducing a feature that lifts the shadows, called D-Lighting. Canon answered with HTP (Highlight Tone Priority), a feature in EOS 40D, which did absolutely nothing, except changing the figures for ISO in the viewfinder from 200 to 2oo. The next step from Nikon was to introduce yet another alteration, which actually did something more than lifting the shadows, Active D-Lighting. Then Sony introduced something they called DRO (Dynamic Range Optimisation), and Panasonic joined in with iAuto (Intelligent Auto), and there are some others too. Just like Canon's non-feature, the Panasonic one was dysfunctional (did nothing), so I'll stay with the Nikon variety, which actually does something:

When Nikon introduced D-Lighting, they implemented it in most of their cameras, including the small compact cameras. D-Lighting is a simple function, and in the compact cameras it was applied to the jpeg image after it was first processed normally. The effect is to brighten the shadow areas, getting more detail in the shadows. In the system cameras, the processing could be applied from RAW, with less risk of posterisation.

The second step by Nikon was to make it "active", by Active D-Lighting. Active D-Lighting sets the light meter to read highlights and to hold them back by exposing less if needed to preserve highlight detail. Therefore, when Active D-Lighting is set in a Nikon camera, sometimes exposure can be held back up to two stops, to avoid clipped highlights. This is done at the moment of exposure, so also the RAW file is different from when Active D-Lighting is not set. Effectively, in a sunny environment, normal setting may set a shutter time of 1/500, while Active D-Lighting could set 1/2000 for the same lighting situation. The result is supposed to be a file with no clipped highlights (cloud fringes etc).

I cannot say how Fuji might have implemented it, and I don't know most other cameras. The ones I have tested thoroughly for the function are Panasonic Lumix G1 and Canon EOS 40D, which both boast of having such a function, but none of them does anything else than altering the ISO figures in the display. Nothing at all, nil!

However, in all Nikon cameras with the function it is fully functional and does what it is designed to do. It holds back exposure in a conservative way when highlights are present, and the D-Lighting function brightens the shadow areas with a different tone curve for the jpegs.

Of course the same can be done with any camera, measuring highlights and setting exposure for them, and processing the RAW file to display more shadow detail. Many of us prefer to have control of what the camera does and how our images are processed, so we might fancy other methods than an obscure automatic function.

To find out what the Fuji does, just as with any other camera, you'll have to test it under controlled conditions.

[John 2]

Thanks Robin for a particularly clear explanation. Ditto Urban although sadly I am now Nikon-less. When I had a D7100, I did wonder what D-Lighting was all about (I clearly don't devour handbooks) but too late now. I might trial it on the Fuji but since it's buried in the menus, by the time I have selected it the shooting opportunity may well have passed.

[Black Pearl]

I don't know what ISO free means. Searching the net I find ISO free and ISO less. I think, not sure, they are the same. What I understood is that the result of a picture taken at let's say 800 ISO will be about the same as a picture taken at 200 ISO and give it in PP an exposure correction of +2 stop.


This one I don't understand. I think the camera has a base ISO of 200. To get a underexposed picture with the same settings of S and A the ISO must be 100. Is upping the base to 400 the same?



How can the high lights have more details when the exposure is underexposed?

* Yes - sorry it seems I used the wrong term
* The camera stops you using base iso to give it more wriggle room. You can only select 200% if you have the ISO set to 400 or higher and you can only set 400% if you have the iso on 800 or higher.
* Because an under exposed shot is darker meaning the highlights are far less likely to exposure beyond the sensors recovery capability.

[Black Pearl]

Thanks Robin for a particularly clear explanation. Ditto Urban although sadly I am now Nikon-less. When I had a D7100, I did wonder what D-Lighting was all about (I clearly don't devour handbooks) but too late now. I might trial it on the Fuji but since it's buried in the menus, by the time I have selected it the shooting opportunity may well have passed.

Which Fuji do you have?

You should find the DR Mode in the Q Menu and so long as you have the ISO on Auto or high enough to trigger it the setting is easily switched between options. If you are shooting street (where the Fuji excels) and are taking advantage of the film simulations then the extended DR is a great asset to getting the most from the jpeg engine.

Its dark here now but tomorrow if I get a chance and the weather isn't as miserable as it was today I'll try to show the DR Modes in action.

[Black Pearl]

I am old enough to remember the Broadway Musical Play, "Annie Get Your Gun"...

It contained a song that was very appropriate to the difference between in camera processing of JPEG images and the photographer's post processing of RAW images. The song went. "Anything you can do, I can do better. I can do anything better than you"

Yes and no.

The Fuji crowd are a bit of a weird bunch (I'm on the fringe but lean towards the unusual at times) with many of them hell bent on only shooting jpeg and using the Film Simulations along with H-Tone/S-Tone and other adjustments to get results straight out of the camera. The new X-Pro2 has an extra monochrome film simulation (ACROS) which is getting users of older bodies howling at the moon in the hope they get a FW update to their cameras. In Fujiland it is ALL about the jpeg to the point where the only talk you will find about raw is the arm waving, hair pulling, cross-eyed, rabid, manic discussions around the pro's and con's of LR against other conversion software. If you want a laugh go to a certain well known photographic site, join the discussions and say you don't see the point in using anything other than LR to process a Fuji RAF file. The resulting meltdown will baffle you for years to come.

[george013]

* Yes - sorry it seems I used the wrong term
* The camera stops you using base iso to give it more wriggle room. You can only select 200% if you have the ISO set to 400 or higher and you can only set 400% if you have the iso on 800 or higher.
* Because an under exposed shot is darker meaning the highlights are far less likely to exposure beyond the sensors recovery capability.

It looks the same as Active D-lighting with Nikon, with the ISO as the variable.
I think to be used when the contrast in your scene exceeds the dynamic range of the sensor only.

George

[Black Pearl]

It looks the same as Active D-lighting with Nikon, with the ISO as the variable.
I think to be used when the contrast in your scene exceeds the dynamic range of the sensor only.

George

I think there is more going on than in Nikon's D-Lighting which I have also used. It is very difficult to get a solid answer regarding the way Fuji present data, even their raw files aren't quite what they seem. For instance the raw data you as a user gets isn't quite the same as the sensor outputs - there is noise reduction/shaping/jiggery-pokery applied and I think some manipulation of the DR even without the fancy boost being talked about here. It is cheating to a degree but if you read my post regarding Fuji users it seems to work.

[xpatUSA]

Yes and no.

The Fuji crowd are a bit of a weird bunch (I'm on the fringe but lean towards the unusual at times) with many of them hell bent on only shooting jpeg and using the Film Simulations along with H-Tone/S-Tone and other adjustments to get results straight out of the camera. The new X-Pro2 has an extra monochrome film simulation (ACROS) which is getting users of older bodies howling at the moon in the hope they get a FW update to their cameras. In Fujiland it is ALL about the jpeg to the point where the only talk you will find about raw is the arm waving, hair pulling, cross-eyed, rabid, manic discussions around the pro's and con's of LR against other conversion software. If you want a laugh go to a certain well known photographic site, join the discussions and say you don't see the point in using anything other than LR to process a Fuji RAF file. The resulting meltdown will baffle you for years to come.

Not just the Fuji crowd, either. The Sigma crowd, with their latest Foveon Quattro-sensor cameras, are declaring OOC JPEGs to be as good, if not superior to X3F raw.

Pure heresy, of course, especially to a Quattro non-owner.

Sigma SD1 Merrill Raw vs. Embedded JPEG:



After due conversion from raw to TIFF and hours of post-processing in RawTherapee- but no work at all on the embedded image - it should be obvious to all that raw is superior.

Or is my comparison just a tiny bit unfair?

[Manfred M]

I think there is more going on than in Nikon's D-Lighting which I have also used. It is very difficult to get a solid answer regarding the way Fuji present data, even their raw files aren't quite what they seem. For instance the raw data you as a user gets isn't quite the same as the sensor outputs - there is noise reduction/shaping/jiggery-pokery applied and I think some manipulation of the DR even without the fancy boost being talked about here. It is cheating to a degree but if you read my post regarding Fuji users it seems to work.

I suspect this is similar to what Olympus and Panasonic do with their raw files. They embed lens correction data in the raw data files. Sony is rumoured to have done something along those lines as well, but they (like FujiFilm) seem to be less transparent about it.