HDR and linear gamma

Processing
21

OK, will post later today

22

Here is the sidecar file from RT

_04A4126.tif.out.pp3 (12.0 KB)

Here is the RAW file
_04A4126.CR2 (29.0 MB)

The way I generate the graphs is with Mathematica

I can send the code, but unless you have Mathematica it won’t work.

Basically, what I do is extract an 800 x 800 pixel image from the center of the frame, with this

imagemiddles = Map[ImageTake[#,middle800rows,middle800cols]&,alltifs,{2}];

Here is the imagemiddle for ISO 100, and conversion by RT

middleiso100rt.tif (3.7 MB)

To measure SNR I convert the image into an array of real numbers with ImageData

Then I use this function

perchannelsnr[imagedata_]:= Map[Mean[#]/StandardDeviation[#]&,Transpose[Flatten[imagedata,1]]];

That simply takes the 2D array of pixels, makes it into a 1D list of pixels, separates by channel, and then takes the mean and the standard deviation and makes the ratio.

After that it is just bookkeeping to do it for different ISO and different raw converters

23

Whoops, I made a mistake. The 800 x 800 “middle” file I posted above is not the one from RT, it is the one from darktable.

Here are both of them, correctly this time. Sorry for the confusion

middleiso100dt.tif (3.7 MB) middleiso100rt.tif (3.7 MB)