Rational Ratios

Lighting ratios?
This term refers to the way photographers describe both the quanity and the quality of their lighting.

Huh? Ok, no quiz but the lighting ratio is the measure of the amount of light (in f/stops) that illuminates the highlights compared to the shadows.

The first number in the formula refers to the main or key light; the second is for the shadows or fill light.

Ok...so? Well, the closer the two numbers are to each other, the flatter the overall lighting. Thus, contrast is good thing. The more the ratio varies the higher the overall contrast.

And, why do we care?

The importance of proper lighting ratios is that it will help you retain important detail in your shot. How often have you noted blown out highlights or too dark shadows that kill all of the detail in an otherwise great shot? Bad lighting ratio equals too much or too little contrast. Therefore, just like Goldilocks, we want the ratio just right!

The ideal ratio is 6:1. If your camera can capture a 6-stop range of highlight to shadow detail you are shooting in tall cotton...so to speak. If your scene has a lighting ratio of 7:1 you must drop your light levels in the highlights or add light to the shadows to reach the 6:1 ratio.

Typically, ratios can be determined with your camera's in-camera spotmeter. Costly hand held flash meters are frequently used by the pros; however those of us who are more casual shooters we are money ahead if we stick with our camera's spotmeter.


Speaking of light and lighting...check this webblog on lighting. A number of great tips and hints as well as some pretty nice work. Give it a look, you'll feel better and be healthier too.
http://strobist.blogspot.com/