Setting light ratios

[joe_bailey2]

I am using a Sekonic L358 meter. With the dome down, I measured and adjusted

my main at f/11, fill at f/8 and hair at f/8. Each light was measured by

itself with the others off. If I raise the dome, point at the camera and fire

all flashes, the reading is now f/13. Am I to set my camera to f/13? Is this

common for the total light reading to increase? If I want the final aperture

to be f/11, should I lower all the flash levels. Thanks.

[brooks short]

Joe, measure it again with the dome out, making sure that the hairlight isn't hitting the dome of your meter. Set your exposure to that reading which will probably be 1/2 stop more than the main light at f11.5 (f13).

[pacorosso]

What you have is an issue with enviromental light. Measure again your lihgts but with all the lamps switched on. If you are going to measure your key light, with your hand, cover the other lamps. So you can read the actual light coming from the direction of the key light, not only the light of the key lamp. This illumination "coming from the keylight" is the bounced light of the rest of the lamps, the diffuse and scatered light from all the space surrounding the scene and the refleted light of the equipment. This the is, the enviromental light. Remember this: in the illumination of an scene you have two spaces: the "field" (the parte of the scene your light fall over) and the enviroment: all the space surrounding the field which REFLECTS over the surfaces of the things you have to photograph.

repeat the measurement with all the lamps. Measure always with all the lamps switched on and cover with the hands the direct light from the "other" lamps over the photometer.

[jim c]

Joe.

 

You did it the right way. You can leave the dome down to measure the individual lights. That's how you determine the ratio's. Then with the dome up you point the meter at the camera from the subject position and that's your taking aperture so you had it right. If you want to adjust the taking aperture you do have to adjust all the lights up or down to get where you want to be. That's why it's nice to have lights that adjust in 1/10 stops. It's easy to dial them up or down to get the proper setting.