I thought it would be good to explain why ALL digital images need to undergo some sharpening.
A digital camera sensor is made up of millions of tiny lenses, each one captures one colour and a brightness level. Then through an amazing process, this analogue light capture is turned into the digital colour image we see on our LCD's and Computer screens.
Below is an image of a sensor, sitting on a Bayer pattern filter, one of a few methods used to capture our images, but probably the most common.
Now each pixel site is a small (we are talking microns) width, and they laid out side by side, checker board style on the image sensor. Like this:
(image courtesy IBM, taken with an electron microscope of an actual image sensor)
Notice how each pixel site is separated by that small area (the tan part in the image above), well that is the reason why ALL digital images need sharpening. Your images when captured have a small area between each pixel site on the sensor where no light is captured (we are talking really small), but that 'dead' area, means that all digital images are not as sharp as they could be straight out of the camera. The technology inside your camera fills in this 'dead' area by alligning the data from each pixel up against the data from the neighbouring pixels, it is clever, but the result is your digital images straight from your camera will always be a little soft.
So sharpening your digital images is an important part of your workflow.
There are various methods of sharpening available, most commonly used would be USM (Un-Sharp Mask) a term carried over from film and dark room processing. It is worth investigating other sharpening methods (and there are a few).
I hope this has helped members understand why they need to sharpen their digital images.
I am leaving this thread open as members can discuss the various methods they employ to sharpen their images, and other members can learn of maybe better ways to do it.