Why it matters.
Plan what fits in a frame before choosing a lens or position.
A closer look.
For a given sensor, shorter focal lengths include a wider angle. With the same focal length, a smaller sensor records a narrower portion of the image.
Picture this
Imagine cropping the edges from an unchanged picture. That illustrates narrower coverage without moving the camera.
Keep in mind.
Specify the sensor format when comparing focal lengths. Angle-of-view measurements can be horizontal, vertical or diagonal.