When using Lightroom, you might be wondering why the highlight recovery between different camera models allows for different room. Given the “color of light” (light source color temperature and tint) is the same, the highlight recovery difference depends primarily on baseline exposure compensation applied to a raw file when it is opened in Adobe raw converters (Adobe Camera Raw, ACR; or Lightroom, LR). This baseline exposure compensation is applied behind the scenes, the exposure compensation slider after the file is opened stays at zero. This is Adobe’s way to equalize cameras.
The amount of the behind-the-scenes compensation depends on the camera model, ISO setting (it is different for Lo settings), and rendering (if you pick something like Camera Vivid, it may be different). To check the BaselineExposure value, one can download the Adobe DNG converter and convert some test raw files from his camera(s). To see BaselineExposureOffset too, one can just save DNG from ACR or LR with appropriate Camera Profile. Next, download the EXIFTool software and run the converted files through it, like:
exiftool -model -iso -BaselineExposure -BaselineExposureOffset -T *.dng
I put several files through and the results are:
| Camera Make and Model | ISO | BaselineExposure | BaselineExposureOffset |
|---|---|---|---|
| Nikon D600 | 100 | 0.35 | – |
| Nikon D610 | 100 | 0.35 | – |
| Nikon D700 | 200 | 0.5 | – |
| Nikon Df | 100 | 0.25 | – |
| Nikon D800 | 100 | 0.35 | – |
| Nikon D800E | 100 | 0.35 | – |
| Nikon D3 | 200 | 0.5 | – |
| Nikon D3S | 200 | 0 | – |
| Nikon D3X | 50 | -0.75 | – |
| Nikon D3X | 100 | 0.25 | – |
| Nikon D3X | 200 | 0.25 | – |
| Nikon D4 | 100 | 0.25 | – |
As you can see, using the Adobe Standard process, the number for BaselineExposureOffset is at zero (if it is present for your camera, add it to BaselineExposure).
From the table above, you can see that for Nikon D3X at ISO 50 (Lo setting) 0.75 EV (stops) is subtracted, making the image “darker”, while for ISO 100 0.25 EV is added, making it “brighter”. You can also see that the compensation (and thus the room for “highlight recovery”) differs between the D3 and the D4 by 1/4 EV, more “room” for the D3. The difference between the D3 and the D3S is 1/2 EV, favoring in this respect the D3; however in fact it means that the D3S exposure is already hotter, adding to less noise.