Any light, when it strikes an object, will do one of three things. The light energy can be absorbed, in which case it is converted to some other energy such as heat. It can be reflected or refracted. In most cases, it will do some of all of these things. The reaction most people expect is the reflection.
Put a wide angle lens up to your eye and things look farther away and some objects look distorted. Do the same with a telephoto lens and objects look closer. They seem magnified and objects appear compressed. This phenomenon is called perspective distortion and some folks would say that each lens provides a different perspective. But how’s this for shaking things up?
Perspective is not controlled by the lens.
By definition 18% gray is the “mid-point between black and white on a logarithmic or exponential curve.” Think of it this way; it is simply halfway between black and white. It is the average in terms of scene brightness and has for many years been the one constant thing that photographers use on which to base their exposures on.
In camera TTL meters are incredible tools that help provide very accurate exposure settings. But as accurate as they may be, the camera can only measure light that has been reflected or produced by a subject of which it has no idea what it is. For the most accurate metering, photographers use incident light meters to measure the light from the source before it strikes the subject.
