Differences in sharpness due to variable light conditions (contrast)

Street scenery on a cloudy day

Although it is ultimately a matter of subjective judgment, generally a sharp photograph is one in which the details are in focus, the exposure is well balanced, and there is a good sense of contrast. When the camera is set to autofocus, you have no direct control over the aperture or shutter speed, so when the light conditions alone are taken into consideration, there will be a clear difference in sharpness between photos taken outdoors under sunny conditions and those taken in poorly illuminated interiors. A photograph with a fair degree of light contrast will still look sharp even if the highlighting is poor in places.

Street scenery under a clear sky

Compare:Understanding Printers/The edges of the principal subjects are unclear