When a camera is focused, the lens is moved away from or...

When a camera is focused, the lens is moved away from or toward the digital image sensor. If you take a picture of your friend, who is standing 3.90 m from the lens, using a camera with a lens with an 85-mm focal length, how far from the sensor is the lens? Will the whole image of your friend, who is 175 cm tall, fit on a sensor that is 24 mm $\times$ 36 mm?

Labs

Want to see this concept in action?

NEW

Explore this concept interactively to see how it behaves as you change inputs.

View Labs

Key Concepts

Sensor Format and Field of View

The sensor format, defined by its physical size (for example, its length and width), determines the camera's field of view, which influences how much of the scene or object will be captured in the image. Understanding the sensor dimensions is essential for evaluating whether the entire image of an object, after being magnified by the lens, fits within the sensor boundaries.

Lens Magnification

Magnification is the ratio of the image size on the sensor to the actual size of the object. It is linked to the distances determined from the thin lens equation and is crucial for understanding how the size of an object is represented on the sensor. This calculation helps in assessing whether the full subject will fit within the sensor’s dimensions.

Thin Lens Equation

The thin lens equation relates the focal length of a lens to the distances of the object and the image from the lens. It is expressed as 1/object distance + 1/image distance = 1/focal length. This relationship is fundamental in optics to determine how far the lens must be placed from the sensor to achieve a focused image of an object at a given distance.

Transcript

Please give Ace some feedback