where do you get the idea that dt clips? i don’t think it does. the fast version of the algorithm requires to quantise the input brightness levels, essentially limiting the preciseness/usefulness to [0,1] on the input. outside, you’ll get halos. i don’t see the algorithm as scene to display mapping. i think it’s a local contrast algorithm in display referred space (hence your log mapping before it).
fwiw it’s my understanding that the original intent may have been to transform the coarse residual after doing only a few levels of laplacian pyramid, then putting back the laplacian coefficients starting from the transformed coarse.