RawTherapee: Flat fields (basic questions)

Software RawTherapee
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I rediscovered RawTherapee a couple of days ago. To my amazement I found out that the software can apply corrections using Flats and it does so in the most straightforward and sensible approach imaginable, while providing a reasonable degree of control over the process. I have a few questions though.

  1. I capture all my Flats with the camera in the Horizontal orientation. The actual photographs can be taken with the camera in all sorts of positions: Horizontal, Vertical - rotated 90 degrees to the left, Vertical - rotated 90 degrees to the right. Is RT smart enough to read that data in the RAW files and use the Flats in the orientation that matches that of the photos. What happens in the case where the camera orientation is recorded incorrectly, or not recorded at all? Like when shooting straight up or overhead?

  2. I’ve read some of the documentation, though I was unable to find anything about the actual exposure of the Flats. Should I expose the flats at the meter’s reading, or should I let in another stop or two? What’s the proper way?

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  1. Yes. Your photos are actually all stored in the same orientation, it’s just the metadata which tells the program accessing them to rotate them if necessary.

  2. The less noise in them, the better. I expose mine with the spike lying anywhere between the middle of the histogram to before clipping.

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Can you average a bunch of flat fields to minimize noise?

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Wow… That was stupid of me. Of course all the raw files are saved in the same orientation… I should have known better.
Thanx!

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@CarVac IIRC dark-frames yes, flat-fields no. You can do that in-camera. Dark-frame merging functionality needs to be improved, and when we get around to that it will be used for flat-fields too.