STEP BY STEP HOW TO USE F-STOPS ON A 3D CAMERA
01 INITIAL SETUP
In this scene created in Cinema 4D with Redshift, I have three elements – the car, the woman and the lighting curtain – all set up for a studio shoot. The camera is set with an 80mm lens to focus on the woman. This ‘portrait’ lens has been set with an F-stop of f/8. This is a good intermediate F-stop for capturing all of the elements in the shot.
02 BLURRED OUT
In this image, I have switched the camera to have an F-stop of f/1.2. This is a typical maximum aperture on more expensive lenses and as we can see, with the focus still on the woman, the car and light curtain are now blurred out, allowing the woman to be the point of interest.
03 SHIFTING FOCUS
Keeping the aperture to f/1.2 but shifting the focus point to the front of the car, the woman and the front of the light curtain now become blurred. If animating by simply controlling only the focus point, the point of interest can be changed in a scene without having to worry about complex camera moves. This is a common technique when working with characters that are speaking.
04 KEEP ADJUSTING THE APERTURE
This time I have physically moved the camera to the woman and refocused on her face. I have changed the aperture to f/4. Even with this narrower aperture, the car and rear light curtain are still out of focus. This is because the closer focus distance has meant that the depth of field is much narrower. Experiment with camera position and aperture to create a scene which retains a point of interest but still makes the background blurring ‘photo’ realistic.