Originally Posted by clemmb
That my friend is the 100% crop...[] The borders of your screen are cropping your image. If you selected a rectangle anywhere from that region and discarded the rest and save, that would be a 100% crop. As said by others, it is what we use to "pixel peep" and judge the sharpness or noise or IQ of an image. So, when people post 100% crops they are posting a portion of the image that represents a full 100% zoom on your's, mine, Daniel's, and everyone else's monitor screens.
Hope that clarifies.