Lighting Ratios

I have learnt a lot recently from studio practice sessions about lighting, portrait lighting mainly. I've learnt about some of the styles of lighting and their uses, also about some of the technical aspects of lighting using key (the main light) and fill (secondary lights or reflectors) lights. Lighting ratios are the difference between the key and the fill lights. You can find out this ratio by using a light meter to measure the aperture value needed at the dark and the light areas, the number of stops difference is then converted into a ratio, so if there's only one stop difference it is 2:1 lighting ratio if their is two stops difference it is a 4:1 lighting ratio.This is because of the fact the light is either halved or doubled coming into the lens (see my post on aperture).

2:1 Ratio using Low Key Lighting.

1:1 Ratio using mid key lighting.


I have found this information I have learnt really useful and will be using it when I delve more into studio portrait photography.