RT overexposing/clipping .RW2 files from Panasonic S cameras

Hello everyone,

I’ve had problems with processing .RW2 files taken with the Panasonic S1, S1H and S5 in RawTherapee (5.8) since there occurred a lot of clipping in the images. I first thought that this had been a problem of the cameras tending to overexpose in automatic metering. But it turns out that this is due to RT clipping values of the raw camera files.

When I use Adobe DNG Converter to turn the .RW2 files into DNGs, (significantly) less clipping occurs. On top of that, the raw histogram of the images differs:

raw histogram of original .RW2 file, with clipped highlights

raw historgram of the above file converted into .DNG, clipping is gone

Can you post an example .RW2? I’d like to open it in rawproc, absolutely no processing of the libraw-decoded array.

Here are both an original .RW2 and the converted DNG:

P1026315.RW2 (34.3 MB)

P1026315.dng (24.6 MB)

It seems that RT interprets the values of the .RW2 file 2 stops over.

EDIT - The following two files show the difference perhaps even better:

P1026319.dng (25.4 MB)
P1026319.RW2 (34.3 MB)

I opened both files, and both definitely have clipping from the camera. Here’s a screenshot of 6319; hope it’s see-able, consider the histogram to the left to be the 14-bit data binned in the 16-bit container. Note the spike on the right side, that’s sensor saturation at 16383, all three channels.

6315 has a similar spike, less pronounced.

Now, the histograms you posted definitely include some processing; if you want to see the linear data, I think you need to select the RT neutral processing profile.

Thank you so much for looking into this! - But even if I apply the RT neutral profile, I get vastly different exposures and clipping, as well as different raw histograms for .RW2 and .dng respectively:

DNG file, processed with RT neutral profile

RW2 file, processed with RT neutral profile

Raw histogram for the DNG file:
DNG raw histogram

Raw histogram for the RW2 file:
RW2 raw histogram

Works fine in RT dev build

1 Like

@heckflosse - thank you!

I plunged into installing the dev build (Linux appimage), and this indeed resolved the whole issue.