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Best way to light a background for portraits

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John P.

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I'm having a difficult time to get the proper separation of subject and background in my portrait shots. I have my subject about 8 feet away from my background, but still the background seems to be right behind them and lit from edge to edge. Right now I'm using a AB400 w/10 degree grid to try and get the separation but no luck. What am I doing wrong and what can I do to improve the separation. I have a sample below of a test I tried....



--
ZM Rapid .20

Soon: ZM Rapid .25
 
I would move the key light off to one side and use a reflector for fill or use the AB400 for fill and things will improve. I like to use a large SB for key and an umbrella for fill with this configuration. Also, try a 30 deg grid on the background instead or better yet get things down without the background light before you try to light the background.

Here is one from a few weeks ago of my nephew's girlfriend using this approach-

 
John P. said:
no..the AB400 w/10 degree grid is pointed at the background. I
should have mentioned that the key light is an AB800 in a medium SB
directly above the subject pointed down for a butterfly effect.
Click to expand...
You should be able to tell the results by hand metering the normal
positions. Your background can be equal or several stops below
the position of your subject. At eight feet, you should be able to
meter the background down to almost very dark.

You can meter and send that info to the forum for more comments.
Test by placing your typical distance and the turning the background
lights completely off. Slowly increase the power at a given distance
until you get what you want.

Lastly, you can make sure your key, fill, and overhead strobes have
modifiers that reduce the spill light on the background. Having them
as angles that do that really helps.

I think the real solution is to make use of your hand meter. It saves
a great deal of time when you can really know the difference in
stops between different positions in your set. Its much easier to
dial down any light to get the lighting you want.
 
Feather it away from the subject so only the EDGE of the light hits the subject and the center points nearly perpendicular to the subject. Examples with medium SB and grid on BG:





Joe
 
John P. said:
John P. wrote:
no..the AB400 w/10 degree grid is pointed at the background. I
should have mentioned that the key light is an AB800 in a medium SB
directly above the subject pointed down for a butterfly effect.
Click to expand...
...you can darken the background as compared to the subject by;

1) reducing the power of the background light through various means, or;

2) increasing the power of the key light and changing the aperture (smaller aperture, larger number) to keep the same exposure (this would also give more depth of field, which may be a plus or minus), or;

3) making a snoot of some sort to confine the background light to exactly the desired area.
 
Joe...very nice! So, was your key light 90 degrees or so to the left of your subject?
Joe Marques said:
Feather it away from the subject so only the EDGE of the light hits
the subject and the center points nearly perpendicular to the
subject. Examples with medium SB and grid on BG:





Joe
Click to expand...
--
ZM Rapid .20

Soon: ZM Rapid .25
 
Thanks. The light was 45 degrees the the left of my camera then I turned it RIGHT until most of the light missed the subject and just the outer edge of the SB caught the subject. 4x6 panel reflector on right provide fill.

Big key mentioned above as well - the light should be no more than 2-3 feet from subject - I get as close as I can without being in the frame.

Joe
John P. said:
Joe...very nice! So, was your key light 90 degrees or so to the left
of your subject?
Click to expand...
 
Joe...what f/stop were you using on those photos? Looks like your background is nicely OOF. How far were the subjects from the background?
Joe Marques said:
Big key mentioned above as well - the light should be no more than
2-3 feet from subject - I get as close as I can without being in the
frame.

Joe
John P. said:
Joe...very nice! So, was your key light 90 degrees or so to the left
of your subject?
Click to expand...
Click to expand...
--
ZM Rapid .20

Soon: ZM Rapid .25
 
Butterfly lighting tends to be used for fashion, where the models are wearing makeup to provide the visual clues that indicate facial contours. Emphasis on the makeup is needed because the lighting is somewhat flat, similar to direct flash. Note that your lighting has also caused unattractive shadows to show under the eyes. With butterfly lighting one would typically have a reflector bouncing from below and onto the face to fill in these shadows.

I would not advise using butterfly lighting for traditional portraiture. In the case of your example photo it would be better to move the key light camera right and lower, and add a reflector camera left for fill.

As for the background, it appears that the key light is spilling onto the background. Try turning off the background light and see how things look. If there is spillover, you need to address this first. With the key off to the side and pointing toward the model, there will be much less spill. The best light control is provided by a softbox.

I don't think the background is too close, instead I think your aperture is too small. I note that the background is in relatively sharp focus, but that is not what you want. I suggest using f/8-f/5.6 for full-frame and f/5.6-f/4 for a crop camera to provide some background blur, which will increase the separation from the subject.

FWIW, most of my studio portraiture is done using a crop camera and 60mm lens at f/5.6 with the subject about 5 ft. from the background. The softboxes are typically just out of camera view. The background is usually crinkled black background paper with a color filter over the background light.

-Gene L.
http://ttl-biz.com
 
I think you are confusing the background light with kicker light (also called separation light).These are two different lights with different purposes.

The kicker is aimed at your subject from behind, and you usually set it 1 stop higher than your key light to greate a "rim" of light that is made more or less invisible by the lightness of the background.

As far as I can tell, you do not have a kicker there, which is why the image becomes "glued" to the background.

Correct me if I'm wrong, anyone :)

--
http://www.digitaldias.com
 
Hey John,

Don't get too worried about lighting the backdrop unless it is white.

Also your big gap and high vantage point have led to the seam from horizontal to vertical angle of the backdrop to be half-way up the photo!

There are plenty of ways to get the subject lighting you want and backdrop lighting you want. I only directly light the backdrop when I want to use gels, or a light behind the subject's back, or a whiteout effect:


















John P. said:
I'm having a difficult time to get the proper separation of subject
and background in my portrait shots. I have my subject about 8 feet
away from my background, but still the background seems to be right
behind them and lit from edge to edge. Right now I'm using a AB400
w/10 degree grid to try and get the separation but no luck. What am
I doing wrong and what can I do to improve the separation. I have a
sample below of a test I tried....



--
ZM Rapid .20

Soon: ZM Rapid .25
Click to expand...
 
Hey Joe,

I'm after a backdrop similar to yours. Where did you get yours, if I may ask.
Joe Marques said:
Feather it away from the subject so only the EDGE of the light hits
the subject and the center points nearly perpendicular to the
subject. Examples with medium SB and grid on BG:





Joe
Click to expand...
 
Gene L. said:
I don't think the background is too close, instead I think your
aperture is too small. I note that the background is in relatively
sharp focus, but that is not what you want. I suggest using f/8-f/5.6
for full-frame and f/5.6-f/4 for a crop camera to provide some
background blur, which will increase the separation from the subject.

FWIW, most of my studio portraiture is done using a crop camera and
60mm lens at f/5.6 with the subject about 5 ft. from the background.
The softboxes are typically just out of camera view. The background
is usually crinkled black background paper with a color filter over
the background light.

-Gene L.
http://ttl-biz.com
Click to expand...
Gene is right. Your solution is in the aperture. It should not be wider that about f/5,6 on a crop camera. A camera with a smaller sensor size cannot be used if you want your background out of focus.

In my studio the background is at about 3 ft behind the subject, focal length usually 85mm.

Feathering your light is a technique used for lighting your subject, I use it almost always, but not for lighting the background.

Leen Koper
http://www.fotografieleenkoper.nl
 
As someone else here already mentioned, the best way to control the lighting on the background is by using the laws of physics, in particular the inverse square law
by moving the main (and fill if you are using one) closer to your subject.

For example, you say your subject is 8 ft from the background, but you don't mention how far your light is from your subject. If your light is 8ft from your subject and also lighting the background there should be one stop difference between your subject and background. If you move the light to 4ft and dial down the power so the aperture is the same you now have two stops difference between your subject and background.

When I get a new background I generally shoot a reference series showing how the background looks from slightly overexposed to several stops underexposed and then with a gridded background light with different exposures so I know how it will look with a separation light added. When I decide what mood I want to create I have a pretty good idea what distance I will require my subject to be from the background and what distance I will need my lights from my subject to get the base exposure on the background.
 
Bill McLeod said:
As someone else here already mentioned, the best way to control the
lighting on the background is by using the laws of physics, in
particular the inverse square law
Click to expand...
The inverse square law is used to approximate gravitational attraction, this I know - but I don't feel it would be accurate as a rule of thumb for lighting.

Does your exposure drop by half if you stand twice as far back from your subject? No!
 
LiveM said:
Martin wrote:
...I don't feel it would be accurate as a rule of thumb for lighting.
Click to expand...
While the inverse square law applies most precisely to a point light source which shines light in all directions at equal intensity, it still comes very close and is very helpful in most photographic lighting situations. See this link, and/or about 74,000 others that come up with a Google search;

"...an object that is twice the distance from a point source of light will receive a quarter of the illumination."

http://www.geofflawrence.com/photography_tutorial_inverse_square_law.htm
 
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