Optically impossible but artistically feasible

I added the background behind this telephoto shot -- the original showed just the sky behind the giraffe -- and what's interesting about it is that the long lens would have produced an out of focus background due to the shallow depth of field inherent in telephotos.  Here, however, the distant trees are sharp.  A painter can do that, but photographers are governed by the laws of optics. The focal length of the lens I used here was 640mm -- the 400mm setting on Canon's 100-400mm telephoto plus the 1.6 crop factor on the 7D Mark II.  A lens this long would never have produced a sharp background, especially when the giraffe was fairly close to the camera position and the landscape details were much farther away.  By combining two sharp images like this looks unusual to a photographer, but it makes sense if you think in terms of a painting.  I find this technique to be quite compelling, and I plan to experiment more with it.  The settings for this shot of the giraffe were 1/2000, f/5.6, 1000 ISO.