Please help me with white background lighting!

Discussion in 'Lighting Equipment' started by brandon_andreadakis, Apr 3, 2011.

  1. Hello,
    I am relatively new to studio work. I love the look of a pure white background and have been researching how to do it for a few weeks in my spare time. Anyway, I got a light stand and a white muslin background. I also got 1 Alien Bees B800 strobe and a medium size Paul C. Buff softbox. I set the muslin up today in a roughly 20 x 20 room with a few windows. The muslin is wrinkled up pretty bad, but I had read that that is not a problem with enough light thrown at it. If it makes a difference, the muslin is 10x20. Anyway, I attached the softbox to the B800 and cranked it up to full power. I had it of to one side of the backdrop feathered as evenly as possible over the entire backdrop. The light reading was at like f20 in the middle and f18 towards far side. I shoot a D90, so the lowest ISO I can really go is 200. So that is 1/250 at f20. What was weird was that in order to get a completely blown out background, I had to shoot it at f8. So...then I placed a large item I am selling on ebay in front of the background. That metered at like f2.8 with ambient light, so that's where I shot it. The result was AWFUL. The top of the item was blown out. The front of the item was underexposed to the point that you could see all the wrinkles in the muslin under it, etc... So, I figured I would try something else. I put my old D70 on a tripod and placed it about 10 feet in front of the backdrop. I took some shots of it. It was so..."milky" is what comes to mind...but better than the previous shots. When I played with the aperture value, I was either too dark or too light. Nothing seemed to work. The worst part of it all is this really annoying "ghosting" I think it's my lens. I figured it was coming from the light box, but I moved further back and shot, and it actually got worse. What am I doing wrong? I have my first shoot with a model this Friday coming up, so I really need to get this down by then. If the ghosting is in fact from the light, how do I get it to stay on the backdrop. Everyone seems to be using a different kind of reflector and/or homemade contraption for background modification. I figured worst case scenario for Friday is I don't light the background and just use it as a gray background, but with it as wrinkly as it is, I don't think that's possible either. Lastly, how far does my subject have to be from the backdrop? The backdrop is 20 feet long. If I have it 10 feet high, that only gives me 10 feet total to work with. With lights and all, that leaves pretty much nothing. How big of a background do you guys get for infinity shots? If I want to use it as an infinity, I don't know how it is possible as I am getting so much spill. Please tell me what I need to get/do!!! I am looking for an infinity background, PURE PURE white with a lot of contrast and clarity in the subject. If you tell me that I need more lights, just go ahead and say so. I have 1 more B800 on order. Will 2 B800's light a 10x20 backdrop? What is the best pre-made modifier for this? I don't really want to build anything. For cost reasons, I was hoping I could get away with 2 lights and a reflector, but I don't think that's happening now that I'm reading more and more about white backgrounds.
  2. The secret is lighting in layers: separate lightign o nthe background from your the main light on your subject. With flash i nan otherwise normally lit room you don't have to worry about shutter speed. Ignore the ambient light reading unless that is your key.
    Ideally you use a pure white background -- Savage Super White paper is the standard. You light it from both sides or if you have a boom and sufficient ceiling height, one light from above can work. If you are using an incident type meter tha treads the light falling on it, generaly you don't need the background be to lit no brighter than about a half to a full stop brighter than your key subject light -- a 2:1 ratio . Given that your background is around f18 and the lightr eading on your subject is f/2.8 your ratio is more like 30;1 and the background is effectively bright enough for your camera to see it as a light source. That is a recipe for detail destroying flare, hence the milky rendering of the subject. If I were were you, I'd get two AB400s and large softboxes, some large (48 x 98 inch) fomecore flats (white or black) and a good lightmeter tha treads flash.
    I'd also get a copy of "Light: Science and Magic", third edition, and postpone your date for a week or two while doing some serious studying and experimenting. That will do a lot to allay your panic.
  3. Thank you for your response. I get the feeling that a lot of my problems stem from how wrinkled the backdrop is. I have been watching videos, and nothing is quite so bad as mine. So...I am pumping a ton of light into the backdrop to compensate. You are correct about the flare...when I metered ambient, I get a U.E. reading. With the backdrop strobe connected to my meter, I get enough spill to get me to 2.8 in front of my subject. So, I 'll have to get some of that paper you speak of. As far as the modifier, you are recommending softboxes? Won't I get the same type of spill I have now? Should I get a softbox with a grid?
  4. This is a great page:
    Although the background in the photos ranges from white to gray to black, and even red or green, all of the photos were photographed using the same white background.
    There is an excellent 8 part tutorial on how to do it that starts here:
    If you have a hard time finding all of the tutorials, all of the links are here:
  5. Thanks! Great links! What's funny is that the link with the tutorial talked about the Nikon 50mm 1.8 being terrible with flare. That was what I was using...
  6. Just a thought. With a model coming Friday, that doesn't give you a lot of time to practice. I would go ahead and use the white background for some photos, but I would suggest you also use one or two Alien Bees to light the model and use a black backdrop a fair distance behind the model so it goes totally black. It can be very effective and it will eliminate a lot of lighting complications.
  7. Brandon.
    If you don't have a flash meter....get one....a good one like a Minolta III or IV or one of the Sekonics. You need one that will read both incident (for the subject) and reflected (for the background).
    You need at least two more lights and they need to have lots of power. Two more of the Alien Bees will be adequate, but I would buy all the power you can get.
    Then, as others have said, dump the muslin except for standard portraits and invest in a good set of background stands and the Savage Super White background paper. Do not use over carpet as it will be destroyed.
    Here's the formula. Place one light on each side of the background at enough distance to cover the area with the lighting pattern. They should be placed at about subject height. Place them at 45 degree angles to the background and pointed somewhat outboard of the center so you get as much brightness toward the sides as possible. Use these at full power only!!!! Now take your meter in reflected mode and made a flash reading off of the background center at subject height and from about three feet away from the paper. This is your baseline from which to establish what the subject brightness will have to be for proper exposure while keeping the background pure white.
    With the reflected reading method (the only accurate measurement for the background because using incident would risk favoring one light over another and giving a false measurement), you can then calculate the needed subject brightness to be two stops less than that of the background. Example. If the reflected background reading is f16, you want to arrive at an incident subject measurement of f8 or two stops less bright. The camera will be set for the subject brightness only!!!!!!
    For the subject, use ONLY incident measurement on the meter because different subjects will have different reflective qualities. You need to know how much light is arriving on the subject, not how much it is reflecting. If your reading happens to hit at two stops less than the background, great. If not, you will need to adjust the power on the subject lights (not the background). Be sure that after you adjust power, you discharge the lights before taking the new incident reading as the capacitors have to dump the old amount of power and recharge to the lessor (or greater) new power amount before you can get an accurate meter reading for comparison. Keep on adjusting until you get the two stop difference (not a 2:1 ratio) that you need. That's it. Not difficult with the right gear and the right set of rules. Works perfectly for film or digital.
    As to the issue of floor brightness, with the background lights blasting toward the super white paper, you now get the benefits of the physics of angle of the incidence/angle of reflectance rule. Simply put, so much light bounces off of the background onto the floor and at such a perfect angle back toward the camera off of the hard coated and quite shiny material, the floor will appear almost as bright as the background itself....probably not more than half a stop off without using any lights directed at the the floor itself. If that isn't bright enough in practice, go to Lowe's or other building supply company and buy a couple of cheap sheets of white wall panel for a shower enclosure to cover the floor under the subject. Those will reflect even brighter than the paper.
    Good luck.
  8. What kind of light modifiers do you all use for high-key background lights? Unfortunately, I only have 1 light to devote to the background (AB800) with a 20 degree honeycomb grid. This results in a hot circle that fades to gray around the edges (unless I really overexpose).

Share This Page