In my opinion, the subject should be sharp, and the background CAN be unsharp. In this picture the subject seems 'the landscape' to me.
Joachim,
Look at landscape paintings. There's a distribution of sharpness and detail from front to back. When photography started, the effort was made to get as much information as possible. Soon however, the lenses where too good and things became harshly sharp. Also illumination of hte perphery lost attention for the subject.
Then we started to get brilliantly designed soft focus lenses and the great custom in dodging and burning to vignette and build a picture that directed interest. The camera merely documents where it's pointed. We have to build a picture. We do that by
finessing the importance of things both before and after releasing the shutter.
For a survey for land use or for crime scenes, astrophotography, science in general, identifying every person in a soccer stadium crowd to find missing felons, cameras, in almost all cases, need to be as and evenly illuminated as possible.
Today, with megapixel races and lenses with even illumination to the edges and RAW workflow that corrects things anyway, we are faced with an image which is directed by technology of uniformity, not esthetics and ranking of importance. That's our job!
Unless one is doing portraits with a wide aperture or images of landscape with compromised DOF, or special lighting or composition, we really need to review what we have. This is the question we have to ask ourselves time and time again, for each and every picture and each and every part of the image we want to present.
The camera-made the decisions, do they express the feelings we find so special about the subject or do we need to intervene?
I prefer to see folks fingerprints on the picture in ranking all effects possible.
Asher