Reply to thread

Message: <blockquote data-quote="Al Gentile" data-source="post: 415331" data-attributes="member: 35690">"I'm still working on grasping 18% grey though."Back in the early 1900s, Kodak engineers determined that if, in a 'typical' scene, you averaged all the colors and brightnesses, you'd end up with the color grey that reflected 18% of all the light that fell on it.  Thus, light meters were calibrated to assume that they were always pointed at an 'average' scene, and would recommend the proper combination of aperture and shutter speed (for the given ASA [ISO]) that would correctly render the proper exposure.  Although that's clearly sometimes a mistaken assumption, it makes more sense than to assume the scene was always brighter or darker than normal.Nowadays your camera's meter is still based on the same assumption - that the scene in front of it is 'average'.  If the scene is brighter or darker than average, then the meter will recommend the wrong exposure.  Matrix metering is less likely to be confused than the other metering modes (e.g. spot, center-weighted), but it can still be confused in some tricky situations.Luckily, the BLUE sky (away from the sun, no clouds) is about as bright as a 'grey card' which reflects 18% of the light falling on it.  Thus, if you 'zero' your meter when pointed at the blue sky, you'll be setting the proper exposure for anything else in the same light.  If you then recompose & focus, you can ignore your meter, which may have subsequently varied from the 'blue sky' recommendation when you recomposed.Hope that helps.Al</blockquote>

Verification