Blended composite of 2 images shot w/1Ds. 3-stop range, layer blended in PSCS. Horizen blends are started with the gradation tool over a layer mask and tweaked with various brushes. One of the niceties of the mask method is that the backslash key will toggle the mask and corrections can easily be done by changing the opacity and or color of the brush, with the very simplest 'undo' just going from a black colored brush back to a white one.