Originally Posted by
Geoff F
I think, Brian, that is a mixture of camera angle, distance and subject texture. The 'nose' is fine, also top of the head including its eye is well focused; but the 'cheeks' on the right side are beginning to lose sharpness. This is possibly due to the round shape of its head which is putting the bottom right corner area beyond the focus depth of the nose and eye.
Some insects, and flowers, lack sharply defined edges to colour changes etc. Moths are particularly problematic in this respect. If you over sharpen them their individual surface scales become too obvious which creates a mosaic type of pattern that appears unnatural.
Hairs look strange when viewed from directly above which can be problematic in identification. For example, something like deciding between 2 or 3 strong bristles in a particular area can be tricky from some angles. It may be obvious from one angle but only look like one strong bristle plus an odd small spot from another position.