Friday, August 10, 2012
How Lens Focal Length Shapes the Face & Controls Perspective: A Lighting Tutorial! By Jay P. Morgan
The lens or Focal length of the lens you choose has a profound impact on the image. It effects the perspective, background, and features of the subject. Everyone should understand what the different focal lengths do to the human face and how they change the background. Why do you choose a 135 mm lens to shoot a head shot of a beautiful woman but use a 24mm to shoot a clown? Keeping the head the same size in the frame and changing the focal length of the lens, I shot a series of images that demonstrate how focal length effects the features of the human face and how it changes perspective which effects the background. In this test we see that longer focal lengths flatter the face and shorter focal lengths make it look distorted and comical. I prefer to shoot a head shot with a 100mm to 135mm focal length lens on a 35 mm camera. This keeps the face from distorting and gives a nice look to the subject.
When shooting on a set there is no set rule when it comes to lens focal length. Longer lenses need less set and shorter lenses need the subject to be pushed close to the background or a larger background. If you keep the subject the same size in the frame when changing the focal length it will change the perspective of the image. Things push farther away from the camera with shorter lenses and come closer with long lenses. The person's face also will change just as we saw in the first test. We will need to balance the look of the person's face and body with the perspective we desire in the background. I love to play with different prespectives on set, using different lens.
This is the final image in the lighting portion of our lesson. Let's break down the lighting and post process that created this image.
We are shooting a tight face shot, of lovely Rebecca Grant, with this two light and one reflector fashion lighting set up.
Our first light is a medium strip box behind the subject on camera left.
It's up high to rim her hair and shoulders. The Dynalite pack is dialed one and a half stops higher than the camera exposure to give us the highlight.
Now we will add an extra small Photoflex Octodome as our key light. It's placed on a c-stand so we can place it over and slightly above the lens.
The silver octodome gives us a wonderful highlight on her face. It's placed above the camera giving her a butterfly light on her face. You can see the loop below Rebecca's nose and the strong shadow under her chin. Even though I love the butterfly light something will need to be done to soften the shadow under her chin.
To soften this shadow we will add a silver/gold reflector to bounce light under her chin and soften the shadows on her face overall.
The reflector has softened the shadows and given us a nice light on her face. I'm ready to shoot now. I'll shoot two or three hundred images before we are done. This will give me plenty to choose from.
Her is our final image before we go to Nik Sofware for the post process.
In the post process i took the image into Nik Software Pro Efex 4 and made some changes. I started with a bleach bypass filter and turned the opacity down 55 percent on the layer.
I then used the Film vintage filter and turned this layer down 40 percent. I liked everything at this point except the white reversed vignette. It's too strong. I had complete control to set the value of the vignette when I created this layer. I set it a bit heavy so I decided to reduce it with a dark vignette layer.
Here is our final image. I love this look, so I decided to apply it to an additional image.
Here is the raw image.
This is the finished image.
We have seen how lens focal length shapes the face and changes perspective. This information will help you make decisions about what lens to use when shooting. Choose a lens that will communicate your creative vision for a particular image. Lens perspective is a critical part of the creative process and should be considered when shooting.