Portrait Photographers, light ratios?

There seems to be no set industry term for a one stop difference between main and fill. Some call it 2:1. some call it 3:1. Dean Collins called it 1:3. What term do you use and why?

I gave DJ M a thumbs down because it wasn't an answer to the question, but an opinion.

Please see, I am asking about a ONE stop difference.

This is a question of semantics, but I have a reason for wanting an answer.

Ratio refers to the number of stops between the highlight side and the shadow side.

So on a sunny day, F16 @ 125. If you turn the model so you have a ratio from the small light source (the sun), one side of the face is highlit, one is in shadow. If you expose at f16@125th, the ratio in the image will be 3:1 - the shadow side is 2 stops below the highlit side.

A 2:1 could be achived be using a flash with a output of GN32 and syncing it off camera from 4 meters to the shadow side of the model - GN32/f16= 2meters - we want 1 stop under for a 2:1 so the flash is placed 4meters to the shadow side.

So one stop highlite to shadow face ratio shot is a 2:1 - , if its more stops different then its 3:1, 4:1 et cetera.

Ops just re read the question.......sorry

I was taught to say 3:1 not 1:3, why dont really know, most I have worked with in this area have called it 3:1 also......



:)

I do not think DJ M deserves two thumbs down for his answer. If all photos were based on some written in stone numbers, there would be little to no creativity or art in it. What he says is right on the money.

I DO use light ratio for portraits, but I do not concern myself if it is one or two or three stops different from the key light. Who gives a rat's behind? I have sure never had a client refuse their portrait because my light ratio did not meet their standards.

But to specifically answer your question, I would call it 3:1 if I was using 3 stops less light for fill. I suppose it would be just as "correct" to say 1:3 though. I was just under the impression that the key light was always given the priority, so that is the first number stated.

steve

i hate it when photographers try to boil things down to numbers, its just plain stupid in my opinion. id say set up the lights and see how it all looks, take several photos to see how it appears on the camera.