This week Britt Hogg and I worked in #UofSC_SJMC’s photo studio tweaking the hair light location. Our test images demonstrate how you can use your exposure to control your background. In the first photo, the room is well lit. But in the second photo with a wide open aperture, fast shutter speed and low ISO, the overhead light is so underexposed, it’s insignificant. Only the strobe light is strong enough to show up.
Britt in center of studio, with hair light shining on his head. (See snoot at top of the frame.) One fluorescent overhead light is also on in studio. Photo taken with iPhone, ISO 100; F2.2 @ 1/8 sec.
Lights are set exactly the same as in the previous photo. This time photo is taken with DSLR at ISO 100; F5.0 @ 1/250 sec.
This technique can be useful in several ways. In the case demonstrated, we needed the overhead light in order to focus the camera. No need to turn off lights to take the photo.
In this case, we turned a grey background to black. But you can turn any background black, as long as you don’t throw any light on it.
My Life in Pictures 