In the most basic terms, sharpness is how well-defined the edges of objects appear in your photos. It is a function of the resolution of your sensor, the resolving power of your lens and the accuracy of your focusing. With the massive increase we’ve seen recently in the power of digital camera sensors, as well as ever-improving lens and AF technology, modern digital cameras are capable of producing astonishingly detailed images. Take a look at this photo, shot on a 10.1-megapixel Canon EOS 40D digital SLR:
The photo contains a huge amount of detail, and it would produce a very good A3 print. Even if we zoom in to 100 percent magnification the picture still looks sharp:
However if we zoom in a little further (to 200 percent) we can see that there is a limit to the sharpness. Details such as the frames in the windows and the name on the side of the hotel are slightly soft and lack edge definition.
Let’s take a closer look at how digital cameras use sharpening, and why they need it…