In this graph, brightness differenc

In this graph, brightness differences are expressed as EV values based on the Middle Tone. The vertical axis of the graph is the output level (8-bit color). Level 0 is black, while level 255 is white. This graph shows how brightness differences in the subject will appear as brightness differences on a photograph. More specifically, by using a light meter to measure the brightness of a subject, it is possible to know how the brightness will appear in the photograph based on the exposure setting of the camera. For example, after you measure the highlights in a subject, you can determine numerically whether the measured area can be reproduced photographically (without blooming or highlight block up). You also can numerically determine whether the shadows can be reproduced photographically (without pixel noise or grain). Some digital cameras have highlight and shadow warning functions, but the applied light meter uses an EV scale, which makes it easier to check for blooming highlights or grain shadows using the number of aperture or shutter speed steps.