In photometry illuminance is the total luminous flux incident on a surface, per unit area . It is a measure of the intensity of the incident light, wavelength-weighted by the luminosity function to correlate with human brightness perception. Similarly, luminous emittance is the luminous flux per unit area emitted from a surface. Luminous emittance is also known as luminous exitance.In SI derived units, these are both measured in lux (lx) or lumens per square metre (cd·sr·m−2).
Both the illuminance and the lighting level are measured with the photometer. There are objects capable of producing their own light like the sun or the light bulbs: they are the light sources. Other objects reflect the light and direct it toward our eyes. This is the case of the house opposite my window: it looks like a chameleon. Framing is always the same, but the light is constantly evolving. And this is a basic lesson in photography: take advantage of the good lights.
Both the illuminance and the lighting level are measured with the photometer. There are objects capable of producing their own light like the sun or the light bulbs: they are the light sources. Other objects reflect the light and direct it toward our eyes. This is the case of the house opposite my window: it looks like a chameleon. Framing is always the same, but the light is constantly evolving. And this is a basic lesson in photography: take advantage of the good lights.
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