Jeremy was lit in the great Rembrandt tradition, one flood and, well, NO fill. The group was asked to guess the lighting ratio, 2:1, 4:1, 6:1, 8:1 they said, we measured the light falling on Jeremy's face (an incident light reading) and Mr Sekonic told us it was f32, an incident reading of the light (such as it was) falling on the shaded side was f1.4, a total of 9 stops difference, that's a 512:1 lighting ratio. (remember 1 stop difference = 2:1, 2 stop difference = 4:1, 3 stop difference is 8:1 and so on) Good portraiture is in the range of 2:1 to 8:1 depending upon needs.
Then we wanted to know what exposure to use in this situation. I've always recommended taking different types of light readings. If each of the reading types agree then all is right with the world, if none agree you might be in trouble, if most agree and one is different but you know why it's different you're doing just fine.
We took an incident reading from Jeremy's nose back to the camera position (recommended procedure) and it indicated f22, then reflected spot reading of a grey card in front of Jeremy's nose (also recommended) that said between f22/f32. They are both pretty close but we then took a reflected spot reading of Jeremy's lit cheek and that indicated between f32/f45. So what to do. The incident here would have been a fine call as far as exposure but the other readings were used to confirm the result. The grey card was slightly different because it can change depending upon the angle of the grey card to the light - realistically it was virtually the same reading as the incident. The reflected spot reading of Jeremy's cheek indicated there was 1 stop more light reflected from this compared to the grey card, that's correct since a grey card is ZONE V, skin is ZONE VI and does reflect 1 stop more light. Had we used this reading to expose the shot it would have been 1 stop under, skin rendered as mid-grey, to correct this you would increase the exposure by one stop, ie. between f22/f32, sound familiar?
Incident: f22
Grey card: f22/f32
Skin: f32/f45 (increase of 1 stop = f22/f32
Exposure used was f22
If in doubt slightly more for negative film is OK.
Transparency and digital, use the incident.
:)
