What are Foot Candles?

When you hear someone referring to foot candles they are likely not talking about twelve inch tall emergency candles from their garage. Instead foot candles actually refer to an important measurement that people use in motion film and digital video quite often.

What the foot candle measurement represents is a pure one of the light itself, not one that references the devices of the camera. For example, measuring light in f-stops means that it directly refers to the set shutter speeds on your digital video camera. Instead of this we have foot candles to directly measure how much light is present in a physical situation, or possibly how much is being emitted from a particular light source.

The average way to think about foot candle is that a single foot candle is what we interpret the light from a regular candle to be one foot from that candle light source. A particularly lit situation is then put in these terms, referring to how many candles at one foot distance it would take to achieve the light that is here.

This term is used by a number of different positions in professional situations. Lighting directors, if this is different than the director of photography, will often set according to a specific foot candle number. Directors of photography, at the same time, will usually instruct for specific foot candle readings to be achieved. Different types of video equipment that result in the video image will need to be understood or determined in relation to foot candles. This is a way in which you understand exactly what type of video equipment you are going to need, such as camera reading abilities or film stock.

Take your incident light meter and measure an area, getting a reading on how many foot candles you have. This can take a special type of incident light meter, but check your incident light meter closely and see if it includes foot candles as well as f-stops.

If this is a consideration for you then it is important to find an incident light meter that has foot candles on it so you do not need to use a conversion chart. The use of a conversion chart can end up being more complicated than is practical. If your incident light meter can bypass this then you will find that you will be in a much more practical position to run a production set.