How to create a 3:1 ratio with this 2 light setup?

[dubcat]

My 2 light setup is

- a softbox 45 degrees to one side and above of the subject (key)
- a softbox pointing directly at the subject as close to the lens as possible (fill)

I know I can vary the power of the two flashes in order to create dimensional lighting i.e. stronger lighting on one side than the other.

How do I use my light meter to measure the ratio across a subjects face? I want to create a 3:1 ratio but don't know how to do it.

 

[dubcat]

I did some more reading on this - would the right thing to do be the following?

1) Meter with JUST the key light
2) turn off the key light and set the fill so that the meter reading is 1 stop lower than the key.
3) Turn on both lights and take a new combined reading.

Is that the correct way to do it?

 

[Garry Edwards]

A 3:1 ratio is a difference of 1.5 stops.
To discover what the ratio is (or to set the ratio) you meter towards the light.
If light (a) indicates an exposure of f/8 and light (b) indicates an exposure of f/11 d5, that's your 3:1 ratio. These readings are taken of individual lights, i.e. switch light (a) off when metering light (b) and vice versa.

Of course, to get the correct exposure, you will meter towards the camera with both lights on. The meter will then take account of light reflected from the subject towards the camera, and will also take account of the fact that the fill light will be falling on those parts of the subject that are also lit by the key light, adding to the light in those areas.

Lighting to a ratio is something that I never do. I light to suit the effect that I want to achieve and that is within the capabilities of the medium (film or digital sensor). I never know what the lighting ratio is, but I do appreciate that not everyone agrees with my approach.

 

[dubcat]

Garry - I do agree with your approach of lighting to the effect you want to achieve. The main reason I want to do it methodically/programaticaly in the beginning is to ensure I don't drift too far astray and to leave my mind free to think about other things relevant to the shot. Once I get better at it and some of these other things go on auto-pilot i will use your approach.

For someone like me just starting out and looking for something generally pleasing so they can get on with dealing with mind-bending subject such as posing what ratio would you recommend working to? Is 3:1 a good choice? I tried a 1 stop difference thinking it was 3:1. Will try 1.5 stop difference tomorrow. As I say, this is just for the beginning until my workflow gets fluid enough to allow me to introduce more creative license in to my lighting.

 

[Garry Edwards]

There's no answer to that.

I'm an old man who spends as much time as he possibly can outdoors, in all weathers. My face has 'character lines'. Even totally flat lighting (1:1 ratio) would make me look like an ugly old man,so the best lighting for me might be something like 100:1, to show my 'character'

A beautiful young girl with perfect skin and high quality photographic makeup will probably look best with a 4 stop lighting difference, 16:1. Her mother may look better at 2:1 and her grandmother might look better at 1:1

2:1 or 3:1 is a 'safe' choice in many situations but is highly unlikely to produce the sort of results that people stop and look at.

 

[dubcat]

Thx Garry. I will have a play i always appreciate your help.