Sunlight how many lux

Studies suggest that 1 in 5 of us experience a mild version of the winter blues, while 1 in 20 suffer from Seasonal Affective Disorder SAD. My mood lifts with sunny weather, and with time spent outdoors. Living in northern climates or with poor weather makes getting enough light even harder. Insufficient light during the day has been linked to poor sleep, depression, weight gain and chronic disease.

Days grow shorter, and the intensity of the sun drops 5x from summer to winter in northern latitudes Figure for London in the UK — excerpted from this article. This makes getting enough light in the winter especially difficult for those who live in northern climates. Specially designed bright SAD lights are an effective way to offset the winter blues when days are short and skies are gloomy.

If properly designed, these products can deliver many of the benefits of bright light therapy, without requiring a specific morning exposure ritual. The illumination of a surface at a distance of one meter from this light source is also around 80 lux. When you focus this lument light in a beam, the candela intensity is much larger than when the light is emitted uniformly in all directions.

The illumination of a surface at a distance of one meter from this light source increases by the same proportion to lux. One lumen is defined as one candela over one unit area solid angle. A full sphere is made up of 4pi steradians, so a point light with a luminous intensity of one candela has a luminous flux of First, we removed all the static lighting and ran the Enlighten precompute. These are the first steps in preparing your level for Enlighten lighting.

Next, we added a Directional Light to act as the sun, then added a global Post-Process volume to establish the initial exposure. This is because we want to understand the true effect of our lighting. For example, if we double the intensity of the sun, we expect it to be twice as bright; but if the exposure is automatic, the image will adjust itself to compensate for the brighter light.

This can be misleading. We set the directional light to use three different intensity values: 20, lux, 50, lux, and , lux. These are realistic values for outdoor illuminance at various times of day. Because Enlighten supports floating point lightmaps, we can use really big numbers like these and still get great results. The screenshots below show the level with these different values:.

This is a great start. From here, we can add artificial light sources such as lamps and give them realistic brightness values, and they'll always affect the lighting in a way we can predict. At GDC , we demonstrated an open-world level which takes advantage of real-world lighting units. The scenes range from bright midday sun to a lava-filled gorge.

All the indirect lighting was created with Enlighten. As the demo cycles through different times of day, we used different brightness values for the sun and moon across different times of day and night.

We also used a Sky Light to fill in shaded areas and add color saturation to match the sky color. But once you set up your lighting with real-world numbers, you can experiment with the other effects until you get the right effect. I understood this to mean "staring at the sun directly" - is this correct?

The issue is that I've read other articles that state there are places that receive 40, lux of light. You don't have to look at the sun, you look at the world it illuminates. Lux is a "per unit area" quantity - not a "per solid angle" quantity.

First, there is the candela - "the light of one candle". At the surface of that sphere, the intensity of light per unit area is 1 lux. If you make the sphere bigger, you will have the same number of lumens lumina? For reference, a W light bulb has an output of about lumen; if you wanted a "light as bright as the sun" you would need about 2 kW - and you would have the same illumination at 1 m distance.

Since the total power of sunlight per unit area is about 1 kW round numbers , that is actually remarkably consistent especially given the fact that a light bulb is cooler than sunlight and therefore emits less of its radiation in the visible part of the spectrum. The total light emitted by a body, be it the sun or a fluorescent tube or an LED is measured in lumens. The apparent brightness of the emitter is a function of the amount of light being emitted in relation to the apparent area of the emitter which is why even a small LED torch is painfully bright when you look directly at it but may provide very poor illumination of something you aim it at very small area of LED with relatively few lumens being emitted.

If you stare at the ground in a sun-exposure area, your eyes receives much less than lux. If you stare at a shedded ground in a sunny day, your eyes receive slight less than lux. This is if you point it directly at the sun at mid-day on 1st November, which was at the time of shooting, a clear day.

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