The automatic one-button sharpen function can make a photo appear
crisper. If sharpen doesn't quite make the photo as sharp as you'd
like, use the "unsharp mask" with 3 controls. Do not use the
automatic sharpen twice--it's too much.

The sharpen function doesn't really "sharpen," it finds areas where
pixels change in color or brightness and increases the contrast
between the adjacent pixels. Pay particular attention to the upper
ridge of the bill against the sky.

Here is the original image

Here is the image sharpened 1 times.
This improves the bill and eye contrast.

Here is the image sharpened 2 times.
This makes the photo too grainy and leaves patterns called "halos."

Here is the image sharpened 3 times.

Here is the image sharpened 4 times.
It is staring to look like a painting on canvas.