darktable is changing exposure automatically without me, if I go from to darkroom it changes the exposure, and if I add some effect like sharpen the exposure is set too for that picture, how can I stop this?
You can see in this picture at the bottom how the two images I clicked have different exposure
Default workflow adds 0.7 ev as it also applies filmic. In DT you expose for middle grey so you almost always add exposure and often even 2 to 3 ev This can intially even blow out some of the photo but filmic will map the DNR to correct. You can set workflow preferences to none to avoid DT adding filmic and the exposure…
This is the expected behaviour of darktable, although it may not always be desirable. For instance I do bracketed exposures most of the time, but DT will open them looking very similar in the darkroom. If you look at the exposure module you will see that compensate camera exposure is ticked and the exposure slider is set to +0.7EV. The developer explains why he chose to do this in his videos, but I can see it is not always desirable.
There are a couple of options I could suggest and I am sure others may suggest even better options. The first option would be to create a preset for the exposure module that has the exposure slider set to 0 EV and the compensate camera exposure unticked. However, set black level correction to -0.002 as it helps filmic in the processing. With this option you have to select the preset upon opening the image.
Another option would be to in the processing preferences select none for auto-apply pixel workflow defaults and then create a style which would apply the modules you want to use such as exposure (setup as described in previous paragraph), filmic, etc. I would exclude white balance and raw black/white point module from the preset as these are camera and image specific settings.
I hope this makes sense.
No, it is not 
Unlike most – especially commercial – software, darktable shows a raw file as it is. Firmware in cameras deliberately underexposes images in order to better manipulate data in the highlights and then, no matter if processing in-camera JPGS or loading to Lightroom, Capture One, DXO (…) or manufacturer’s software, the exposure is boosted without the user even knowing. Also, some kind of base curve is used.
Darktable (or RawTherapee for that matter) takes another approach and shows you ground truth.
Darktable can show you “ground thruth”, but if you have selected “scene-referred” as workflow default, it will auto-apply an exposure correction of 0.7 EV, plus the opposite of any exposure correction applied in camera (and it adds a few other modules).
The reason for that extra 0.7 EV is simple. Most cameras cheat and underexpose by 0.5-1EV, they then add exposure when generating the (preview) jpeg… The catch is: the exposure correction from the camera depends on the brand (and model?); for mine, 0.7EV is a bit too low, I have to add about 1EV.
Only if you have selected “none” as workflow default, it won’t apply anything beyond the strict minimum needed to display an image (more or less, e.g. highlight reconstruction seems to be applied automatically as well).
The simple work around is to save a exposure module preset where you uncheck the “compensate camera exposure” box and set exposure to 0. Then make sure this is auto applied to all raw files.
It’s a rather strange assumption by dt that the camera auto exposure is better than what the photographer has manually set.
Is there an overview somewhere which brands and cameras are using which compensation? I am curious if my cameras are affected or if it is only about more recent models.
I think the thumbnail what you are seeing first is just the preview jpg , And the moment you are opening it, it updates it to see the Darktable default rendering.
You can change it in settings somewhere to not use the preview jpg at all, IIRC.
It can also be - like others said - that Darktable is compensating to undo the exposure compensation you dialed in while taking the shot. You can undo this with a single click in the exposure module .
You normally set exposure to prevent clipping, not for how the final image should look. I know a lot of people don’t do it like this, but it is the way to get the most out of modern sensors. I often just shoot -1ev by default for instance if I’m not paying attention to my exposure.
So 'correct exposure ’ is a thing i determine while opening the image, so both DT as the camera have nothing to do with that.
‘recording exposure’ is important, but the camera is often the worst thing to trust then 
It’s actually based on observation: many noticed that they needed to add x EV exposure to get “neutral gray” at the proper spot, compared to what the camera said. So hardly an assumption. And that observation dates from the introduction of filmic. You won’t notice this with the standard basecurves, as they also apply that additional exposure correction, but it is hidden in the curve.
And of course, you can always compare what your raws show relative to your in-camera jpeg (under default camera settings). Or compare what the basecurve module gives compared to filmic.
Oh, and in case you are talking about the automatic compensation of in-camera exposure correction, there’s another thread where this has been treated ad nauseam
Its explained in the manual: darktable 4.2 user manual - process
Not strange at all. Also when the feature was implemented, it was discussed to death here. Its an educated guess, and like most things in darktable, the user is encouraged to create a preset to get what works for them.
As someone who shoots a lot of high dynamic range scenes I often expose like that. But… there are also just as many lower DR scenarios where you use compensation to correctly expose the subject.
The issue is:
So the default isn’t helpful and makes more rather than less work. Of course this only matters to people who photograph a fair bit. If you edit 500 images a year it doesn’t matter. If you go though 10k it does.
@nosle
With the introduction of the exposure matching, for a huge number of images a very decent starting point I find is using the autopicker now in exposure with the setting 50-60% depending on the camera… This often just gives a really nice starting point. If not I try a second time on an roi in the image that should be properly exposed and then if those 2 fail I can manually tweak it…
In addition to this, the initial workflow script created by @Ulrich_Gesing runs this automatic exposure as will as a selectable set of options including automatic application of lens correction, relatvive b and w points in filmic, adding profiled denoise, adding default amounts of global chroma and saturation , you can tweak the wb mode , reset the history stack first or append and it will activate the tone eq and set the mask so it is ready to just make adjustments… It can be run on one or many images and it runs from darkroom or lightable view…
Thats a bit of a diversion but the point is you can have it do a sort of autoexposure on all images and not have to apply a fixed value… and it works generally very well…
Well, then tell us what default would be helpful…
(and create a preset with it for future use, perhaps even auto-apply it?)
Se my first post in this thread. It’s an easy fix as a preset and one I think makes sense as default.
