Why don’t you just deactivate the setting for the scene referred workflow in the options or make your own preset in the exposure module?
I guess the preselected correction of the exposure bias is due to the users feedback of wanting a fast and more automated processing.
But regarding your observation of the different default values for white and black exposure in filmic I also wondered why these settings are chosen in contrast to the default settings of +4/-8 of filmic without the scene referred workflow preset. Especially the black level of -0.002 in the exposure module.
Funny, but by @anon41087856’s definition, that’s exposure, not brightness. As he said, exposure is about capturing light, while brightness is about the rendered JPEG (if I understood him correctly).
Exposure is changing the amount of light that enters the camera (diaph or shutterspeed), or simulating that change by an electrical gain (ISO setting, which electrically “multiply” the signal) or a digital one (exposure correction, which numerically multiply RGB values).
So it sounds like what we need is for the modules to be able to expose an API that can be used by other modules to request information, and for modules to be able to publish updates to other modules that are interested. This sounds like some sort of message queue solution that supports subscriptions could be useful. I guess the first step is to understand what are the message flows we would want to support.
I don’t agree. If the camera rendered the scene’s brightness correctly (people, grass, road), but blew out the sky, which is much brighter, then it’s not an ‘artistic decision’ on my part to apply -1…2EV, but a technical one (kind of what your Fuji does, and my Nikon does not do, or not as well). You could call it a ‘desparate choice’ instead of ‘deliberate choice’. The sky is preserved, but the subject is recorded too dark. Then, loading the image into darktable, it’s very nice that the software can restore the correct exposure for the subject, while pushing the sky over ‘100%’, from where I can bring it back to display-land using filmic’s tone mapping.
I totally agree that exposure is like microphone gain.
But exposure compensation as dialed-in in the camera is only one component of total exposure. That’s why I do not understand why in the filmic rgb workflow, the exposure module by default reverts camera exposure compensation.
I may arrive at the same exposure in multiple ways:
dialing-in exposure compensation
using auto exposure lock
using spot metering
shooting in manual mode
Only in the first case will the exposure module interfere. Isn’t this inconsistent?
Perhaps filmic assumes that the metering of the camera is to be trusted (and is used correctly by the photograph) and the exposure compensation dial is only used for ETTR?
I think that sums it up well. To add to it slightly: you are using a raw processor, so it is assumed you are shooting in a manner that will enable you to get the best output image from processing the raw. And that leads to the assumption that the exposure compensation dial would be used for ETTR.
That is I have to say a very strange assumption. Five minutes after using a camera most people have learned that the camera metering must always be compensated. Not for SNR reasons but basic photography reasons. Besides subject and framing it’s the whole thing with photography.
Even a new super good camera can’t know how the photographers want to expose a scene. The decisions around exposure are as I mentioned a huge part of photography.
Only you know what you shot, what your subject is, where it is located in the frame, and how you want it to look in the final picture. Would you like darktable to automatically figure out the correct exposure? Can you define what ‘correct’ exposure is?
Darktable is not sentinent. Relying on camera exposure as a sensible, close-enough default (or baseline) is, I think, understandable. You can always change it if it does not suit your way of shooting.
There are people here who are much more knowledgeable than me, but I think the assumption that exposure compensation was used for ETTR is implicit in filmic’s reversing that exposure compensation. And that clearly can conflict with raw files taken with the aim of getting a well-exposed SOOC JPEG.
That’s why we have presets and styles: if the defaults don’t correspond to your workflow, you can correct that.
But as there are about as many workflows as there are users, no default setting can satisfy everyone… (E.g. the standard +0.5EV exposure doesn’t fit my camera, but is that a reason to change the default? I trust the devs enough to pick a default that’s more or less correct for most users)
For me and my Canon 80D the default +0.5 EV does pretty well. But I still don’t get why darktable should care how I did my exposure. The compensation is only a tool to get the exposure I want when I use a semi automatic mode. I could just as well have the same exposure in manual. The goal will always be the same, ETTR or not, and the only things that matter are the actual ISO, aperture and shutter speed, not which tools I used to find them.
I agree with your argument but think the current behaviour is trying to second guess rather than just accepting my settings as is.
Perhaps its just me but when ettring I go manual and/or spot metering. Matrix + comp is a bit unreliable and better for more casual stuff. You can easily blow highlights so its better for “normal” exposure adjustments.
You can of course easily adjust exposure to you liking in post. No issue with that. Its just the logic of the default that seems odd.
Agreed, the default behavior of compensating in-camera compensation has pretty much never helped me.
What I always need to do though is to add a lot of exposure (+1 or +2 stops) as the “raw black/white point” module still operates in the [0 - 1] range. Updating that module to align with the rest of the scene-referred workflow would be a neat way of standardizing away that need and be less confusing than having a default +N stops exposure module. Such a change would define a middle grey point instead of a white point to allow for larger than one intensity.
The default grey point would probably best be defined such that darktable middle grey = OOC jpeg middle grey as that would be the least confusing result. Anyone deliberately under or overexposing should expect those images to be under or overexposed in their RAW editor as well.
I think that would be possible to implement using the existing RAW image database, but the highlight reconstruction module would need a bit of rework as a result. Don’t know if it would cause any problems for the white balance or demosaic modules.
As for assuming everyone does ETTR. I’m at least not doing it as noise can be filtered but clipped highlights are lost. So I’m actually rather shooting ETTL
When I first stumbled across this thread I thought it’s only about automatic undoing of dialed-in exposure compensation. Only later I realized that the defaults in the scene-referred workflow do not simply undo the exposure compensation that was set in camera but at the same time adjust the black and white point accordingly inside the filmic module.
I am trying to improve my intuition for what is actually going on here.
This is almost the general rule that filmic applies to set the white and black point by default. That seems to be:
where ExpCompensation is the exposure compensation applied by the exposure module consisting of a constant 0.5 boost and the negative of the exposure compensation that was set in the camera.
Here are some effects of this
We are using an input range of about 12 EV which is comparable to the theoretical 11.7 EV of sRGB. So filmic is not doing HDR-tone-mapping by default.
What the camera thought ought be middle gray will be 0.5 EV brighter in filmic. (Why is there this offset?)
The filmic white and black points will be shifted towards the range of intensities that is properly exposed in the raw file.
I can see the wisdom of this rule for the window example of @kofa (or “ETTL”): since we underexposed the image deliberately, there must be some interesting detail in the highlights that we would like to preserve (the bright window). In order to properly tone map this image, we will want a white point that is relatively farther away from middle gray and this is equivalent to using low paper “hardness”.
However, the same default rule does not seem to make that much sense for ETTR (which is its main advertised use). There, it translates to using a hard “paper” that will help to discern detail in the shadows. However, already at +0.7 EV dialed in the camera, filmic’s default curve becomes non-monotonic (orange lower part) and thus anomalous.
What are some good general rules for setting the white and black point? In general, will one tend to stick with the 2:1 ratio of white point to black point as in the default, or perhaps more with a 1:1 ratio like in the auto filmic style of @anon41087856?
I know that filmic is not supposed to be automatic, but for sure it would be possible to create an auto mode for filmic that better matches expectations for a default usable result. Filmic would stilll allow the same artistic expression, but it would be easier to process huge batches of boring pictures.
There’re no general rules since everybody is just asking for general rules and don’t try several settings and provide the results as a set of general rules.
For a plain well illuminated scene the defaults are quite useful… if not, you need to tweak black or white sliders depending on your expectations of the resulting image…
If you found a general rule, feel free to share …
The sky is preserved, but the subject is recorded too dark. Then, loading the image into darktable, it’s very nice that the software can restore the correct exposure for the subject, while pushing the sky over ‘100%’, from where I can bring it back to display-land using filmic’s tone mapping.