What is footcandle
Footcandle is an amount of light produced by one candle at a distance of one foot. Candles are one of the most ancient sources of lighting, no wonder this measurement is still used even though candles have been replaced by electricity.
A ”pure” footcandle is an imaginary ball of light with a radius of 1 foot and a candle in the center.
The obvious drawback of this parameter – it measures the amount of light, but not its direction and intensity. That’s where we have to call out lumens.
What is lumen
Lumen is a light flow, it’s light emitted by the source. If we want to visualize it, let’s imagine the very same candle, which is based 1 foot apart from the wall and casts light over it. If we draw a square foot on a lit surface, we can assert that it is lit by a light flow of one lumen.
Foot-candle vs lumen vs lux
It is extremely important to understand the difference: lumen is a unit of light, emitted by a source. Footcandle is a unit of light received by a surface. They relate to each other according to the formula 1footcandle = 1 lumen / 1 foot².
What is a lux then? It’s a footcandle’s analog in a metric system. One footcandle equals approximately 10 lux.
Why do we need it
Well, usually we don’t, as long as we don’t work in a site-lighting company. But you can come across those terms while reading manuals to your camera or looking through the settings.
Don’t be scared out: the ultimate majority of modern gadgets measure lighting automatically and you don’t have to bother with it.
But just out of pure curiosity, you may have a look at the approximate lighting recommendations for different sites in footcandles.
Here is a similar list in lumens:
- Living room – 1500-3000 lm
- Bedroom – 2000-4000 lm
- Dining room – 3000-6000 lm
- Bathroom – 4000-8000 lm
- Kitchen – 5000-10000 lm
And don’t forget that even if your technique didn’t manage to catch the lighting correctly, you can always adjust it during post-shooting editing.