The Perfect Backlight pt 2
Our goal is to consider all the important factors when using a backlight. In part one, we went over the best available options at our Baltimore rental studios. Both posts are available on the blog and it is not necessary to read them in chronological order. Lets get to it!
Get your light physically set
OK, so now that you have made the best choice in a modifier for your backlight, it is time to physically set it in place.
The previous article talks a lot about stands and booms and the advantages that booms have when placing a backlight. We are choosing to boom the baby strip box because of its shape, and for the flexibility to do so with a C-Stand. This allows us to place it directly behind Dakota Snow, about three feet above her, and set to an angle that hits both the top of her head, and both of her shoulders… but not the camera’s lens.
As I mentioned earlier, the small strip box is PERFECT for this application, even in small studios. It provides complete coverage as a backlight and can stay just a few feet away. This setup is so low profile, that you could probably use it to shoot a seated portrait subject in a room with only eight foot tall ceilings. Maybe.
A boom is always my preferred way to place a backlight because of how easy it is to aim and still keep out of the frame. The problem with booms is their footprint. Using a slightly modified C-Stand as a mini boom in Studio-B has been working perfectly with the baby strip box and / or the 28” Octabox.
Setting your exposure
Now, we have the back light in place (Alien Bee AB800 @ 320ws) and our subject is set. In the front of our model are our key and fill lights, though their power is irrelevant for this discussion. It is time to set the power of our back light.
As a general rule, I start with my strobes set to half power when I begin a shoot. This is simply so that I know that I have an equal amount of room of adjustment of either side of the exposure. In this case, I knew that the light would be VERY close to the subject, so I set it even lower, at one-sixteenth power! This is an AB800 320 ws.
Lets back up a second and talk about camera settings. For the sake of demonstration, I chose a very ‘standard’ portrait setting.
- Aperture f11
- Shutter 1/160
- ISO 100
I was set to Daylight White Balance, though I believe that Alien Bees are actually around 5200K. It also does not make much difference for this demo.
OK, so now that quarter power setting should make more sense!
The simplest way to test this is to fire the backlight WITHOUT your key and fill lights on; we don’t need them yet!
The results should be a clean and simple silhouette. This view is the perfect way to see the small adjustments (physical and in exposure) that you need to make:
- Is the light hitting both shoulders?
- Does it illuminate her hair on the top of her head?
- Is the light staying out of the lens?
There is no formula on what it ‘should’ look like, but the above questions are the typical concerns to look out for. Also, it is not common for your portrait subject’s shoulders to be the brightest part of the image, so keep the exposure below the highlights as a general rule of thumb.
One your exposure is set, turn on your Key and Fill lights (I recommend setting them all separately, by isolation as well) and you’re ready to start shooting!
On the above left image, you have some 'standard' results. On the above right, the backlight is angled more forward to create an intentional flare in the lens. There are no real rules to this stuff, except to be creative and have fun.
Read more posts like this on the studio's blog.