Lens for a framing
Work backwards from the shot. Enter how much of the subject should fill the frame, across its height or its width, and how far away it is; the calculator gives the focal length that frames it on the selected camera and recording mode.
It also suggests the nearest common prime and shows how much that prime actually frames, so you can see whether to move the camera or change lenses.
How to use it
- Camera: choose the camera and recording mode.
- Subject measured across: height for people and most shots, width for wide compositions.
- Subject size and distance: the size that should fill the frame and its distance from the sensor plane.
- Squeeze factor: for anamorphic lenses; it widens the horizontal coverage.
Example
On an ALEXA 35 in 4.6K 3:2 Open Gate (19.22 mm high), framing a 1 m tall subject at 3 m needs about a 57 mm lens. The nearest common prime is 50 mm, which frames about 1.65 × 1.13 m at that distance.
Good to know
The calculation uses the thin-lens equation with the distance measured from the sensor plane. Real lenses, especially at close focus, breathe and differ slightly from their marked focal length.