Metering for high-key fashion portrait with white BG?

[joseph avalon official sit]

Hopefully I posted this in the right section...

 

I'm trying to achieve lighting results similar to the photo posted below (which

is not my own). I've got a white background and four soft boxes. I'm lighting

the background independently from the subject...but I know very little about

metering so please excuse my ignorance.

 

As I understand it, using my EOS 20D I can do a sort of spot meter with the

partial metering system using a 28-135 IS telephoto lens. Please tell me if the

following is generally the best step-by-step course of action:

 

1) After setting up lights and positioning the model, I do a spot meter reading

of the subject and determine that the correct aperture for the subject is f/8.

 

2) In order to make the background super white I then manually set the aperture

from f/8 to an increase of something like 3 stops. So then I end up shooting at

f/22?

 

Is that how it's done?

 

Do I need to also manually adjust shutter speed or would that be superfluous?

 

Thanks!

[rustymadd]

If you have the BG illuminated correctly (brightly) then move into the model and meter just her skin. Preview the image to get the correct skin value. Check that the background is without details entirely. Take the reading and set your camera to manual at the reading or an equivalent. Shoot away! The skin should be right and the background should take care of itself. The most important thing in the mix is lighting the background correctly so that it is detail-less.

 

C Painter

[rustymadd]

BTW...

 

use any metering mode you wish, just make sure that the skin fills the frame totally.

 

C Painter

[steve_levine]

If you haven't any "film" or processing costs, why don't you simply experiment?

[mike dixon]

<i>2) In order to make the background super white I then manually set the aperture from f/8 to an increase of something like 3 stops. So then I end up shooting at f/22?</i>

No, if you did that, you'd be reducing the exposure by three stops and severely underexposing your model.<P>

If the only meter you're using is the one in your camera, set you aperture to the f-stop you need for adequate depth of field (and make sure you shutter speed is set at or below the maximum flash synch speed). Adjust the output of the lights on your subject until you have her properly exposed. After that's done, adjust the lights on your background until its a true white, but try not to "overcook" the background. If you light the background too strongly, you'll get lots of flare and strong backlighting effect on the model.<P>

One final note: the shot in your link is not "high key." White backgrounds and high key are not synonoymous.

[timsumma]

How to set up a WHITE DROP OUT in studio.

 

The term is A White Drop Out and it comes from commercial Photography. If you want to do it right you will need a white paper called Super White or Artic White, it is the same thing. The guys are correct about lighting your subject plane with one volume of light and the rear with a different volume. The background will need to be 1 to 1 � stops brighter than the foreground. The way you know you are there is that you shoot a test exposure until you get the foreground correct. This is done in MANUAL mode. You then stop the lens down one to one and a half stops. As you look at the background it will just begin to glow blue. The blue is because the UV light from your light source has shifted the background paper to show the glow from the UV whitener that was placed in the paper�s surface during manufacturing. If it requires more than one and a half stops to get the blue you have too much light on the background. Move your light for the subject closer and retest. You can do all this with a digital camera. Last, the exposure is made at the setting for the subject, this cause the background to go white or as the term refers the white drops out.

 

The most important aspect of this type of set-up is to be sure and not blow light off the surface of the paper such that it comes back and strikes the lens creating lens flare. The lens flare part of the white drop out set up is probably the thing that people mess up most when trying this technique. The problem stems from a commonly held missed concept in the world of lighting. Every book that I have ever seen on flat copy work (I�ve read a lot of photo books) has exactly the wrong information in it. For good over all even light illumination that will not interfere by throwing flair into the optical path is for the lights to be set at 30 to 35 degrees to the surface of the copy (in this case the background paper). If you set the angle of your lights to an angle of 45 degrees you will be starting into the creation of strong blow back light. Remember that you are illuminating the paper surface evenly but keeping it from being a strong reflector back to the subject. So set your lights for about 30 degrees and you will get an illumination that works. If you can control the reflectors use ones that are satin surface and moderate in size to get an even light distribution. On a nine foot paper you should be able to do this with two heads.

 

The illustration was done using a set up in which the background was to be two stops above the subject plane exposure. But essentially you can see that the background is dropping out. Subject plane exposure is f 8 and one half, while the background is f 16. I have included the sides and top of the small studio at Mission Road Photography to show the light placement as well as the fact that the ceiling and walls are all matt black, the floor is covered with a black matt canvas throw. I find this excellent control when working in the small studio. Hope this helps.<div></div>

[onewish]

This is how I create a white background.

 

I place my subject about 6 feet away from a whitish wall. I set the lights for the model at about 1/4 power and adjust the camera iso/exposure/f-stop until i'm satisfied with the exposure.

 

I turn off the lights on the model and take two additional lights and place them behind and to the side of the model. Without modifying the camera settings, I take pictures of the white wall (without the model), adjusting the output of the background lights until the histogram is all the way to the right.

 

I hope this helps.<div></div>