ABR800 & Snoot? How to make background black?

So I am trying to create a lighting situation in which my subject is slightly lit and the background is completely dark. I am having a tough time figuring out how to do this with the following equipment:

ABR800
(2) 580ex
White paper backdrop 10 feet wide

Anyone can run me through what i need to do? Do I need to make some sort of snoot? Can't see how I can do that with the ABR800 and moon unit.

Thanks

KFormus wrote in post #9025416
So I am trying to create a lighting situation in which my subject is slightly lit and the background is completely dark. I am having a tough time figuring out how to do this with the following equipment:

ABR800
(2) 580ex
White paper backdrop 10 feet wide

Anyone can run me through what i need to do? Do I need to make some sort of snoot? Can't see how I can do that with the ABR800 and moon unit.

Thanks

the only way to do it with white paper is to make sure ZERO light is falling on it.

You'll need a lot of room to make sure there's no bounced light filling in and making it come out grey.

It'll still be a large technical challenge, even with the snoot. It's that bouncing light which will foil your attempts fastest. Buy black cards, or black velvet, and use that as your background to give yourself a huge push in the right direction.

I would just shoot with the white background, mask out the person in PS, and brush in the white background black.

ugh i hate masking like that. Always looks way fake. I'll use a black bg I suppose lol thx K and logan

Make sure there's ample distance from the subject and background, light the subject and make sure nothing spills to the background.

Super low settings on the flash as well. Something about the fall-off ratio. If you're at f1.4 (or 2.8, or whatever) and have the flash low, by the time it gets to the background it will be the least it can be.

To achieve a pure black background you have to make sure there is separation between subject area and background and no spill from your subject area lighting.

If you have a hand held light meter the key is to make sure your background is 4 stops reflective under your incident subject area lighting.

For instance, if you're subject area lighting is giving you a reading of f/8 incident then you need to meter your background at f/2 reflective.

I doubt that the strength of the stobes will make any difference. The critical elements are (1) the distance of the background from the subject and (2) the depth (not amount) of light on the subject. Ironically, I learned all this back in the days when I used hot lights. Then, I had to put the lights right on top of the subjects to get acceptable shutter speeds at ISO400, and I found that most of the backgrounds would go very dark regardless of the color. Unless you are using black velvet, the background should be far away from the subject (at least 12-15 feet back) and the lights need to be very close to the subject to minimize the depth of the light. Also, use flags to try to stop any light from hitting the background.

It's the ratio of subject area lighting to background. Distance is a great way to increase that ratio but you can turn a background black at very close range as long as you have control over your lighting.

Player9 wrote in post #9027190
I doubt that the strength of the stobes will make any difference. The critical elements are (1) the distance of the background from the subject and (2) the depth (not amount) of light on the subject. Ironically, I learned all this back in the days when I used hot lights. Then, I had to put the lights right on top of the subjects to get acceptable shutter speeds at ISO400, and I found that most of the backgrounds would go very dark regardless of the color. Unless you are using black velvet, the background should be far away from the subject (at least 12-15 feet back) and the lights need to be very close to the subject to minimize the depth of the light. Also, use flags to try to stop any light from hitting the background.

Of course the strentgh of the strobes make a difference.
If you have 8 feet of separation between a subject and a white background what would darken it the most?

Camera and strobes set to light the subject at f16, or
Camera and strobes set to light the subject at f1.4?
Your comment of getting the lights very close to the subject is true, as that is needed to keep the power as low as possible.

get a black background. done.

NaKiD EyE wrote in post #9029210
get a black background. done.

Not true. Even with a black background you have all the same variables that will cause it to render as something other than black. One of the most common things (and popular posts) is to have a black background that is being rendered as dark gray because of spill or an improper ratio between subject area and background.

NaKiD EyE wrote in post #9029210
get a black background. done.

You spill a little light on that black background and you get dark grey. So, not done. In fact, back to square one.

Black background and distance or a very far away/no background. Meaning, outside.